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Friday March 24, 2017

March 24, 2017 at 04:38AM

This Bulletin Valid Until: Sunday March 26, 2017 6 pm. 

DANGER RATINGS (Make sure you understand the danger level meanings)
 
Outlook Friday Saturday Sunday
Alpine HIGH HIGH HIGH
Treeline HIGH HIGH CONSIDERABLE
Below Tree line MODERATE MODERATE MODERATE

Confidence: Moderate

Main Concerns: (Avalanche problems)

Wind Slab-  Wind slabs will be present on lee aspects throughout the forecast period. Up to 50 cm of forecast new snow ,combined with moderate to strong south west and south east winds will promote the development of these hazardous avalanches. During storm events, wind slabs specific to lee aspects and will be touchy to very touch to triggers and large in size( size 2).

Persistent Slab-  Deep and stubborn. A melt freeze crust formed on all aspects and all elevations in mid February is buried down between 80 and 100 cm. In lee areas in the alpine this persistent weakness has been found down 200 cm in depth. Currently this weakness is stubborn to heavy surface triggering. When ideal conditions exist to produce enough load to awake this deep instability, it will produce large to very large avalanches (size 3).

 Loose Wet- New snow and warming daytime temperatures will promote development of loose wet avalanches. Expect to find these on all aspects and at elevations of tree line and especially below tree line. Loose wet avalanches could gain enough mass and be large in size (size 2) and will be very touchy to human triggers during storm periods and when temperatures and freezing levels rise.

Travel/Terrain Advice: Dangerous avalanche conditions exist and travel in avalanche terrain is not recommended.

If users choose to travel during this forecast period, choose low angle well supported simple terrain. Keep a sharp eye on temperatures as they rise and watch for numerous small to large loose wet avalanches that even when small can have severe consequence in terrain where the risk of being pushed over cliff or other terrain trap are present. Look for overhead hazard (cornices) as they are frail and need only the lightest of triggers to fail.

Past Weather: Above zero temperatures followed by a near sea level freezing levels has formed a crust on all aspects and elevations up to 2000 meters. Thursday night, moderate to strong south east winds and snowfall up to 5 cm per hour with alpine temperatures around -4.

Avalanche Summary:  Ski cutting on north aspects at 1350 meters found touchy conditions and produced small (size 1) soft slab avalanches. Failing on the newly formed melt freeze crust down 20 cm and in steep terrain propagated easily. Previous warm and wet conditions produced numerous loose wet avalanches failing to old surfaces in very steep terrain, old debris may still pose a threat to travelers. Numerous cornice tab failures where witnessed as cornices are growing rapidly and remain fragile. 

Snowpack Description New storm snow continues to build and currently sits at 15 cm in most areas. Moderate south east winds have transported to lee aspect much of this snow, creating hazardous avalanche conditions.Previous warm temperatures followed by very cool temperatures have created a 8 cm crust that all of this new snow now sits on and is bonding poorly. The crust  can be found on all aspects and up to 2000 meters in elevation and is very smooth and planar and will be an ideal sliding surface for new avalanches. New and continued snowfall will continue to be sensitive to triggering on this new crust throughout the forecast period.The mid March rain crust is prevalent on all aspects and elevations, up to 20 cm thick and buried down up to 35 cm and bonding moderately well. The mid February persistent weakness can be found between 80 to 150 cm and possibly up to 200 cm in isolated lee terrain in the alpine. Above and below this layer facets are present and are a compounding factor of this instability.This layer is producing easy results when isolated and tested. The mid and lower snow pack are well settled and dense snow pack conditions are found. 

Surface- new low density storm snow sits over top of a 8 cm melt freeze crust

Upper-  between 80 to 150 cm overlie the persistent mid February crust

Mid-  Well settled.

Lower- Well settled.

Weather Forecast: A moderately strong upper low passes directly along the island's west coast bringing to the forecast region south east winds and moderate to heavy snowfall amounts. Western front ranges will continue to receive the brunt of the storm with significantly higher precipitation amounts.

Fri -  up to 45 cm new snow    Winds SW to 40 km/hr.     Freezing level to 1200 m.

Sat-  up to 10 cm new snow      Winds SE to 50 km/hr.      Freezing level to 1100 m.

Sun- up to 15 cm new snow       Winds SE to 60 km/hr.      Freezing level to 1000 m. 

 

Prepared by Jesse Percival

Wednesday March 22,2017

March 22, 2017 at 04:43AM

This Bulletin Valid Until: Friday March 24, 2017 6 pm. 

DANGER RATINGS (Make sure you understand the danger level meanings)
 
Outlook Wednesday Thursday Friday
Alpine CONSIDERABLE HIGH HIGH
Treeline CONSIDERABLE HIGH CONSIDERABLE
Below Tree line MODERATE MODERATE MODERATE

Confidence: Moderate

Main Concerns: (Avalanche problems)

Wind Slab-  Wind slabs will form in the alpine and at treeline during both Thursday and Friday. Up to 100 cm of new snow and rain at some elevations combined with moderate to strong south west and south east winds will promote the development of these hazardous avalanches. During storm events, wind slabs specific to lee aspects and will be touchy to very touch to triggers and large in size( size 2).

Persistent Slab-  Deep and stubborn. A melt freeze crust formed on all aspects and all elevations in mid February is buried down between 80 and 100 cm. In lee areas in the alpine this persistent weakness has been found down 172 cm in depth. Currently this weakness is stubborn to light surface triggering. When ideal conditions exist to produce enough load to awake this deep instability, it will produce large to very large avalanches (size 3).

Loose Wet New snow and rain at elevations below 1500 meter, will promote development of loose wet avalanches. Found on all aspects and at all elevations  tree line and below. Loose wet avalanches could be large in size and will be very touchy to human triggers during storm periods and when temperatures rise.

Travel/Terrain Advice: Dangerous avalanche conditions exist and travel in avalanche terrain is not recommended.

Past Weather: Moderate to strong south east and south west wind with up to 15 cm of new snow. 

Avalanche Summary:  A few small (size 1) loose avalanches reported all failing within the new snow on steep north and west aspects.

Snowpack Description The upper snow pack is settling well under current mild temperatures and precipitation.The mid March rain crust is prevalent on all aspects and elevations, up to 20 cm thick and buried down 20 cm under new dense well settled snow. The new snow is bonding moderately well with resistant planar results reported. The mid February persistent weakness can be found between 80 to 150 cm and possibly up to 200 cm in isolated lee terrain in the alpine. Above and below the layer facets are present and are a compounding factor of this instability.This layer is producing easy results when isolated and tested. The mid and lower snow pack are well settled and dense snow pack conditions are found. 

Surface- well settled new snow

Upper-  between 80 to 150 cm overlie a melt freeze crust

Mid-  Well settled.

Lower- Well settled.

Weather Forecast:  Unsettled spring weather continues,a series of weak disturbances will spin thru the forecast region bringing light to moderate snowfall and southwest and south east winds. Eastern zones will receive substantially less precipitation more sun effect and periods of clearing between storms, while western front ranges will receive the brunt of the storms with significantly higher precipitation amounts forecast. 

Wed -   up to 20 cm new snow    Winds SW to 40 km/hr.     Freezing level to 1500 m.

Thur-  up to 50 cm new snow      Winds SE to 50 km/hr.      Freezing level to 1100 m.

Fri-     up to 50 cm new snow       Winds SE to 60 km/hr.      Freezing level to 1200 m. 

 

Prepared by Jesse Percival

Monday March 20,2017

March 20, 2017 at 04:16AM

This Bulletin Valid Until: Wednesday March 22, 2017 6 pm. 

DANGER RATINGS (Make sure you understand the danger level meanings)
 
Outlook Monday Tuesday Wednesday
Alpine MODERATE MODERATE HIGH
Treeline MODERATE MODERATE CONSIDERABLE
Below Tree line LOW LOW MODERATE

Confidence: low, uncertainty with predicted precipitation amounts and limited upper alpine snow observations.

Main Concerns: (Avalanche problems)

Wind Slab-   Past light to moderate south east and south west wind has formed wind slab in the alpine and at tree line. Wind slabs can be found on lee aspects and located in features such as ridge top areas and steep convex rolls. Avalanches from wind slabs could be large (size 2) and have have been reported to be stubborn to ski cutting but may be touchy to triggers in isolated terrain features.

Persistent Slab-  This persistent weakness within the snow pack is bonding poorly in both the alpine and at treeline. A layer of low density facets overlie the crust and recent snow pack tests produced easy results at treeline. The weakness is located down between 80 and 100 cm. On lee aspects (North East and North West) the persistent weakness is suspected to be down 200 cm. Further heavy loading and very warm temperatures may wake this deep instability and could produce very large avalanches in isolated terrain. 

Travel/Terrain Advice:  Evaluate snow and terrain carefully, seek to identify features and areas of concern. Be especially aware of increasing danger levels as precipitation amounts increase and temperatures and freezing levels rise. 

Past Weather: Up to 20 cm of snowfall and light to moderate south east and south west wind. Cool and clear conditions have formed surface hoar on all aspects. Daytime solar effect has moistened snow surfaces on solar aspects and overnight cooling formed a breakable surface crust.

Avalanche Summary:  No new natural avalanche activity reported in the past 72 hours. Avalanche control teams reported ski cuts produced only small (size 1) loose dry avalanches on steep north west aspect treeline terrain.

Snowpack Description: Clear and cold temperatures in the last 48 hours has created small surface hoar on all aspects and at all elevations.A variety of surface conditions exist and are dependent on elevation and aspect. Moist on solar aspects,pressed and dense on windward aspects, and low density snow on protected north facing aspects.The mid March layer is buried under low density snow down up to 20 cm and is bonding moderately. The mid February persistent weakness is bonding poorly but currently non reactive to heavy surface triggers.This lingering concern will produced very large avalanches when woke and will likely remain a concern for the remainder of the season.Beneath this the snow pack is well settled and dense.   

Surface: Surface hoar up to size 3mm

Upper-  100 to 150 cm overlie mid February melt freeze crust (persistent weakness)

Mid-    Well settled.

Lower-Well settled.

Weather Forecast:  A brief period of high pressure will bring clear and cool conditions for the next 24 to 36 hours. A south westerly flow will follow and produce continued unsettled conditions bringing to the region moderate south west wind, rising freezing levels and temperatures. Snowfall amounts are expected to be moderate with the exception of western zones. Current forecast models predict that in western zones of the forecast region, snowfall amounts may exceed 50 cm.

Mon - trace amounts of snow   Winds E to  30 km/hr Freezing level 1200 m.

Tues- up to 20 cm of snow  Winds S to 50 km/hr Freezing level 1500 to 1600 m.

Wed- up to 50 cm of snow and some rain  Winds SW to 40 km/hr Freezing level 1500 down to 400 m. 

 

Prepared by Jesse Percival

View older posts »

Friday March 24, 2017

March 24, 2017 at 04:38AM

This Bulletin Valid Until: Sunday March 26, 2017 6 pm. 

DANGER RATINGS (Make sure you understand the danger level meanings)
 
Outlook Friday Saturday Sunday
Alpine HIGH HIGH HIGH
Treeline HIGH HIGH CONSIDERABLE
Below Tree line MODERATE MODERATE MODERATE

Confidence: Moderate

Main Concerns: (Avalanche problems)

Wind Slab-  Wind slabs will be present on lee aspects throughout the forecast period. Up to 50 cm of forecast new snow ,combined with moderate to strong south west and south east winds will promote the development of these hazardous avalanches. During storm events, wind slabs specific to lee aspects and will be touchy to very touch to triggers and large in size( size 2).

Persistent Slab-  Deep and stubborn. A melt freeze crust formed on all aspects and all elevations in mid February is buried down between 80 and 100 cm. In lee areas in the alpine this persistent weakness has been found down 200 cm in depth. Currently this weakness is stubborn to heavy surface triggering. When ideal conditions exist to produce enough load to awake this deep instability, it will produce large to very large avalanches (size 3).

 Loose Wet- New snow and warming daytime temperatures will promote development of loose wet avalanches. Expect to find these on all aspects and at elevations of tree line and especially below tree line. Loose wet avalanches could gain enough mass and be large in size (size 2) and will be very touchy to human triggers during storm periods and when temperatures and freezing levels rise.

Travel/Terrain Advice: Dangerous avalanche conditions exist and travel in avalanche terrain is not recommended.

If users choose to travel during this forecast period, choose low angle well supported simple terrain. Keep a sharp eye on temperatures as they rise and watch for numerous small to large loose wet avalanches that even when small can have severe consequence in terrain where the risk of being pushed over cliff or other terrain trap are present. Look for overhead hazard (cornices) as they are frail and need only the lightest of triggers to fail.

Past Weather: Above zero temperatures followed by a near sea level freezing levels has formed a crust on all aspects and elevations up to 2000 meters. Thursday night, moderate to strong south east winds and snowfall up to 5 cm per hour with alpine temperatures around -4.

Avalanche Summary:  Ski cutting on north aspects at 1350 meters found touchy conditions and produced small (size 1) soft slab avalanches. Failing on the newly formed melt freeze crust down 20 cm and in steep terrain propagated easily. Previous warm and wet conditions produced numerous loose wet avalanches failing to old surfaces in very steep terrain, old debris may still pose a threat to travelers. Numerous cornice tab failures where witnessed as cornices are growing rapidly and remain fragile. 

Snowpack Description New storm snow continues to build and currently sits at 15 cm in most areas. Moderate south east winds have transported to lee aspect much of this snow, creating hazardous avalanche conditions.Previous warm temperatures followed by very cool temperatures have created a 8 cm crust that all of this new snow now sits on and is bonding poorly. The crust  can be found on all aspects and up to 2000 meters in elevation and is very smooth and planar and will be an ideal sliding surface for new avalanches. New and continued snowfall will continue to be sensitive to triggering on this new crust throughout the forecast period.The mid March rain crust is prevalent on all aspects and elevations, up to 20 cm thick and buried down up to 35 cm and bonding moderately well. The mid February persistent weakness can be found between 80 to 150 cm and possibly up to 200 cm in isolated lee terrain in the alpine. Above and below this layer facets are present and are a compounding factor of this instability.This layer is producing easy results when isolated and tested. The mid and lower snow pack are well settled and dense snow pack conditions are found. 

Surface- new low density storm snow sits over top of a 8 cm melt freeze crust

Upper-  between 80 to 150 cm overlie the persistent mid February crust

Mid-  Well settled.

Lower- Well settled.

Weather Forecast: A moderately strong upper low passes directly along the island's west coast bringing to the forecast region south east winds and moderate to heavy snowfall amounts. Western front ranges will continue to receive the brunt of the storm with significantly higher precipitation amounts.

Fri -  up to 45 cm new snow    Winds SW to 40 km/hr.     Freezing level to 1200 m.

Sat-  up to 10 cm new snow      Winds SE to 50 km/hr.      Freezing level to 1100 m.

Sun- up to 15 cm new snow       Winds SE to 60 km/hr.      Freezing level to 1000 m. 

 

Prepared by Jesse Percival

Wednesday March 22,2017

March 22, 2017 at 04:43AM

This Bulletin Valid Until: Friday March 24, 2017 6 pm. 

DANGER RATINGS (Make sure you understand the danger level meanings)
 
Outlook Wednesday Thursday Friday
Alpine CONSIDERABLE HIGH HIGH
Treeline CONSIDERABLE HIGH CONSIDERABLE
Below Tree line MODERATE MODERATE MODERATE

Confidence: Moderate

Main Concerns: (Avalanche problems)

Wind Slab-  Wind slabs will form in the alpine and at treeline during both Thursday and Friday. Up to 100 cm of new snow and rain at some elevations combined with moderate to strong south west and south east winds will promote the development of these hazardous avalanches. During storm events, wind slabs specific to lee aspects and will be touchy to very touch to triggers and large in size( size 2).

Persistent Slab-  Deep and stubborn. A melt freeze crust formed on all aspects and all elevations in mid February is buried down between 80 and 100 cm. In lee areas in the alpine this persistent weakness has been found down 172 cm in depth. Currently this weakness is stubborn to light surface triggering. When ideal conditions exist to produce enough load to awake this deep instability, it will produce large to very large avalanches (size 3).

Loose Wet New snow and rain at elevations below 1500 meter, will promote development of loose wet avalanches. Found on all aspects and at all elevations  tree line and below. Loose wet avalanches could be large in size and will be very touchy to human triggers during storm periods and when temperatures rise.

Travel/Terrain Advice: Dangerous avalanche conditions exist and travel in avalanche terrain is not recommended.

Past Weather: Moderate to strong south east and south west wind with up to 15 cm of new snow. 

Avalanche Summary:  A few small (size 1) loose avalanches reported all failing within the new snow on steep north and west aspects.

Snowpack Description The upper snow pack is settling well under current mild temperatures and precipitation.The mid March rain crust is prevalent on all aspects and elevations, up to 20 cm thick and buried down 20 cm under new dense well settled snow. The new snow is bonding moderately well with resistant planar results reported. The mid February persistent weakness can be found between 80 to 150 cm and possibly up to 200 cm in isolated lee terrain in the alpine. Above and below the layer facets are present and are a compounding factor of this instability.This layer is producing easy results when isolated and tested. The mid and lower snow pack are well settled and dense snow pack conditions are found. 

Surface- well settled new snow

Upper-  between 80 to 150 cm overlie a melt freeze crust

Mid-  Well settled.

Lower- Well settled.

Weather Forecast:  Unsettled spring weather continues,a series of weak disturbances will spin thru the forecast region bringing light to moderate snowfall and southwest and south east winds. Eastern zones will receive substantially less precipitation more sun effect and periods of clearing between storms, while western front ranges will receive the brunt of the storms with significantly higher precipitation amounts forecast. 

Wed -   up to 20 cm new snow    Winds SW to 40 km/hr.     Freezing level to 1500 m.

Thur-  up to 50 cm new snow      Winds SE to 50 km/hr.      Freezing level to 1100 m.

Fri-     up to 50 cm new snow       Winds SE to 60 km/hr.      Freezing level to 1200 m. 

 

Prepared by Jesse Percival

Monday March 20,2017

March 20, 2017 at 04:16AM

This Bulletin Valid Until: Wednesday March 22, 2017 6 pm. 

DANGER RATINGS (Make sure you understand the danger level meanings)
 
Outlook Monday Tuesday Wednesday
Alpine MODERATE MODERATE HIGH
Treeline MODERATE MODERATE CONSIDERABLE
Below Tree line LOW LOW MODERATE

Confidence: low, uncertainty with predicted precipitation amounts and limited upper alpine snow observations.

Main Concerns: (Avalanche problems)

Wind Slab-   Past light to moderate south east and south west wind has formed wind slab in the alpine and at tree line. Wind slabs can be found on lee aspects and located in features such as ridge top areas and steep convex rolls. Avalanches from wind slabs could be large (size 2) and have have been reported to be stubborn to ski cutting but may be touchy to triggers in isolated terrain features.

Persistent Slab-  This persistent weakness within the snow pack is bonding poorly in both the alpine and at treeline. A layer of low density facets overlie the crust and recent snow pack tests produced easy results at treeline. The weakness is located down between 80 and 100 cm. On lee aspects (North East and North West) the persistent weakness is suspected to be down 200 cm. Further heavy loading and very warm temperatures may wake this deep instability and could produce very large avalanches in isolated terrain. 

Travel/Terrain Advice:  Evaluate snow and terrain carefully, seek to identify features and areas of concern. Be especially aware of increasing danger levels as precipitation amounts increase and temperatures and freezing levels rise. 

Past Weather: Up to 20 cm of snowfall and light to moderate south east and south west wind. Cool and clear conditions have formed surface hoar on all aspects. Daytime solar effect has moistened snow surfaces on solar aspects and overnight cooling formed a breakable surface crust.

Avalanche Summary:  No new natural avalanche activity reported in the past 72 hours. Avalanche control teams reported ski cuts produced only small (size 1) loose dry avalanches on steep north west aspect treeline terrain.

Snowpack Description: Clear and cold temperatures in the last 48 hours has created small surface hoar on all aspects and at all elevations.A variety of surface conditions exist and are dependent on elevation and aspect. Moist on solar aspects,pressed and dense on windward aspects, and low density snow on protected north facing aspects.The mid March layer is buried under low density snow down up to 20 cm and is bonding moderately. The mid February persistent weakness is bonding poorly but currently non reactive to heavy surface triggers.This lingering concern will produced very large avalanches when woke and will likely remain a concern for the remainder of the season.Beneath this the snow pack is well settled and dense.   

Surface: Surface hoar up to size 3mm

Upper-  100 to 150 cm overlie mid February melt freeze crust (persistent weakness)

Mid-    Well settled.

Lower-Well settled.

Weather Forecast:  A brief period of high pressure will bring clear and cool conditions for the next 24 to 36 hours. A south westerly flow will follow and produce continued unsettled conditions bringing to the region moderate south west wind, rising freezing levels and temperatures. Snowfall amounts are expected to be moderate with the exception of western zones. Current forecast models predict that in western zones of the forecast region, snowfall amounts may exceed 50 cm.

Mon - trace amounts of snow   Winds E to  30 km/hr Freezing level 1200 m.

Tues- up to 20 cm of snow  Winds S to 50 km/hr Freezing level 1500 to 1600 m.

Wed- up to 50 cm of snow and some rain  Winds SW to 40 km/hr Freezing level 1500 down to 400 m. 

 

Prepared by Jesse Percival

View older posts »

Friday March 24, 2017

March 24, 2017 at 04:38AM

This Bulletin Valid Until: Sunday March 26, 2017 6 pm. 

DANGER RATINGS (Make sure you understand the danger level meanings)
 
Outlook Friday Saturday Sunday
Alpine HIGH HIGH HIGH
Treeline HIGH HIGH CONSIDERABLE
Below Tree line MODERATE MODERATE MODERATE

Confidence: Moderate

Main Concerns: (Avalanche problems)

Wind Slab-  Wind slabs will be present on lee aspects throughout the forecast period. Up to 50 cm of forecast new snow ,combined with moderate to strong south west and south east winds will promote the development of these hazardous avalanches. During storm events, wind slabs specific to lee aspects and will be touchy to very touch to triggers and large in size( size 2).

Persistent Slab-  Deep and stubborn. A melt freeze crust formed on all aspects and all elevations in mid February is buried down between 80 and 100 cm. In lee areas in the alpine this persistent weakness has been found down 200 cm in depth. Currently this weakness is stubborn to heavy surface triggering. When ideal conditions exist to produce enough load to awake this deep instability, it will produce large to very large avalanches (size 3).

 Loose Wet- New snow and warming daytime temperatures will promote development of loose wet avalanches. Expect to find these on all aspects and at elevations of tree line and especially below tree line. Loose wet avalanches could gain enough mass and be large in size (size 2) and will be very touchy to human triggers during storm periods and when temperatures and freezing levels rise.

Travel/Terrain Advice: Dangerous avalanche conditions exist and travel in avalanche terrain is not recommended.

If users choose to travel during this forecast period, choose low angle well supported simple terrain. Keep a sharp eye on temperatures as they rise and watch for numerous small to large loose wet avalanches that even when small can have severe consequence in terrain where the risk of being pushed over cliff or other terrain trap are present. Look for overhead hazard (cornices) as they are frail and need only the lightest of triggers to fail.

Past Weather: Above zero temperatures followed by a near sea level freezing levels has formed a crust on all aspects and elevations up to 2000 meters. Thursday night, moderate to strong south east winds and snowfall up to 5 cm per hour with alpine temperatures around -4.

Avalanche Summary:  Ski cutting on north aspects at 1350 meters found touchy conditions and produced small (size 1) soft slab avalanches. Failing on the newly formed melt freeze crust down 20 cm and in steep terrain propagated easily. Previous warm and wet conditions produced numerous loose wet avalanches failing to old surfaces in very steep terrain, old debris may still pose a threat to travelers. Numerous cornice tab failures where witnessed as cornices are growing rapidly and remain fragile. 

Snowpack Description New storm snow continues to build and currently sits at 15 cm in most areas. Moderate south east winds have transported to lee aspect much of this snow, creating hazardous avalanche conditions.Previous warm temperatures followed by very cool temperatures have created a 8 cm crust that all of this new snow now sits on and is bonding poorly. The crust  can be found on all aspects and up to 2000 meters in elevation and is very smooth and planar and will be an ideal sliding surface for new avalanches. New and continued snowfall will continue to be sensitive to triggering on this new crust throughout the forecast period.The mid March rain crust is prevalent on all aspects and elevations, up to 20 cm thick and buried down up to 35 cm and bonding moderately well. The mid February persistent weakness can be found between 80 to 150 cm and possibly up to 200 cm in isolated lee terrain in the alpine. Above and below this layer facets are present and are a compounding factor of this instability.This layer is producing easy results when isolated and tested. The mid and lower snow pack are well settled and dense snow pack conditions are found. 

Surface- new low density storm snow sits over top of a 8 cm melt freeze crust

Upper-  between 80 to 150 cm overlie the persistent mid February crust

Mid-  Well settled.

Lower- Well settled.

Weather Forecast: A moderately strong upper low passes directly along the island's west coast bringing to the forecast region south east winds and moderate to heavy snowfall amounts. Western front ranges will continue to receive the brunt of the storm with significantly higher precipitation amounts.

Fri -  up to 45 cm new snow    Winds SW to 40 km/hr.     Freezing level to 1200 m.

Sat-  up to 10 cm new snow      Winds SE to 50 km/hr.      Freezing level to 1100 m.

Sun- up to 15 cm new snow       Winds SE to 60 km/hr.      Freezing level to 1000 m. 

 

Prepared by Jesse Percival

Wednesday March 22,2017

March 22, 2017 at 04:43AM

This Bulletin Valid Until: Friday March 24, 2017 6 pm. 

DANGER RATINGS (Make sure you understand the danger level meanings)
 
Outlook Wednesday Thursday Friday
Alpine CONSIDERABLE HIGH HIGH
Treeline CONSIDERABLE HIGH CONSIDERABLE
Below Tree line MODERATE MODERATE MODERATE

Confidence: Moderate

Main Concerns: (Avalanche problems)

Wind Slab-  Wind slabs will form in the alpine and at treeline during both Thursday and Friday. Up to 100 cm of new snow and rain at some elevations combined with moderate to strong south west and south east winds will promote the development of these hazardous avalanches. During storm events, wind slabs specific to lee aspects and will be touchy to very touch to triggers and large in size( size 2).

Persistent Slab-  Deep and stubborn. A melt freeze crust formed on all aspects and all elevations in mid February is buried down between 80 and 100 cm. In lee areas in the alpine this persistent weakness has been found down 172 cm in depth. Currently this weakness is stubborn to light surface triggering. When ideal conditions exist to produce enough load to awake this deep instability, it will produce large to very large avalanches (size 3).

Loose Wet New snow and rain at elevations below 1500 meter, will promote development of loose wet avalanches. Found on all aspects and at all elevations  tree line and below. Loose wet avalanches could be large in size and will be very touchy to human triggers during storm periods and when temperatures rise.

Travel/Terrain Advice: Dangerous avalanche conditions exist and travel in avalanche terrain is not recommended.

Past Weather: Moderate to strong south east and south west wind with up to 15 cm of new snow. 

Avalanche Summary:  A few small (size 1) loose avalanches reported all failing within the new snow on steep north and west aspects.

Snowpack Description The upper snow pack is settling well under current mild temperatures and precipitation.The mid March rain crust is prevalent on all aspects and elevations, up to 20 cm thick and buried down 20 cm under new dense well settled snow. The new snow is bonding moderately well with resistant planar results reported. The mid February persistent weakness can be found between 80 to 150 cm and possibly up to 200 cm in isolated lee terrain in the alpine. Above and below the layer facets are present and are a compounding factor of this instability.This layer is producing easy results when isolated and tested. The mid and lower snow pack are well settled and dense snow pack conditions are found. 

Surface- well settled new snow

Upper-  between 80 to 150 cm overlie a melt freeze crust

Mid-  Well settled.

Lower- Well settled.

Weather Forecast:  Unsettled spring weather continues,a series of weak disturbances will spin thru the forecast region bringing light to moderate snowfall and southwest and south east winds. Eastern zones will receive substantially less precipitation more sun effect and periods of clearing between storms, while western front ranges will receive the brunt of the storms with significantly higher precipitation amounts forecast. 

Wed -   up to 20 cm new snow    Winds SW to 40 km/hr.     Freezing level to 1500 m.

Thur-  up to 50 cm new snow      Winds SE to 50 km/hr.      Freezing level to 1100 m.

Fri-     up to 50 cm new snow       Winds SE to 60 km/hr.      Freezing level to 1200 m. 

 

Prepared by Jesse Percival

Monday March 20,2017

March 20, 2017 at 04:16AM

This Bulletin Valid Until: Wednesday March 22, 2017 6 pm. 

DANGER RATINGS (Make sure you understand the danger level meanings)
 
Outlook Monday Tuesday Wednesday
Alpine MODERATE MODERATE HIGH
Treeline MODERATE MODERATE CONSIDERABLE
Below Tree line LOW LOW MODERATE

Confidence: low, uncertainty with predicted precipitation amounts and limited upper alpine snow observations.

Main Concerns: (Avalanche problems)

Wind Slab-   Past light to moderate south east and south west wind has formed wind slab in the alpine and at tree line. Wind slabs can be found on lee aspects and located in features such as ridge top areas and steep convex rolls. Avalanches from wind slabs could be large (size 2) and have have been reported to be stubborn to ski cutting but may be touchy to triggers in isolated terrain features.

Persistent Slab-  This persistent weakness within the snow pack is bonding poorly in both the alpine and at treeline. A layer of low density facets overlie the crust and recent snow pack tests produced easy results at treeline. The weakness is located down between 80 and 100 cm. On lee aspects (North East and North West) the persistent weakness is suspected to be down 200 cm. Further heavy loading and very warm temperatures may wake this deep instability and could produce very large avalanches in isolated terrain. 

Travel/Terrain Advice:  Evaluate snow and terrain carefully, seek to identify features and areas of concern. Be especially aware of increasing danger levels as precipitation amounts increase and temperatures and freezing levels rise. 

Past Weather: Up to 20 cm of snowfall and light to moderate south east and south west wind. Cool and clear conditions have formed surface hoar on all aspects. Daytime solar effect has moistened snow surfaces on solar aspects and overnight cooling formed a breakable surface crust.

Avalanche Summary:  No new natural avalanche activity reported in the past 72 hours. Avalanche control teams reported ski cuts produced only small (size 1) loose dry avalanches on steep north west aspect treeline terrain.

Snowpack Description: Clear and cold temperatures in the last 48 hours has created small surface hoar on all aspects and at all elevations.A variety of surface conditions exist and are dependent on elevation and aspect. Moist on solar aspects,pressed and dense on windward aspects, and low density snow on protected north facing aspects.The mid March layer is buried under low density snow down up to 20 cm and is bonding moderately. The mid February persistent weakness is bonding poorly but currently non reactive to heavy surface triggers.This lingering concern will produced very large avalanches when woke and will likely remain a concern for the remainder of the season.Beneath this the snow pack is well settled and dense.   

Surface: Surface hoar up to size 3mm

Upper-  100 to 150 cm overlie mid February melt freeze crust (persistent weakness)

Mid-    Well settled.

Lower-Well settled.

Weather Forecast:  A brief period of high pressure will bring clear and cool conditions for the next 24 to 36 hours. A south westerly flow will follow and produce continued unsettled conditions bringing to the region moderate south west wind, rising freezing levels and temperatures. Snowfall amounts are expected to be moderate with the exception of western zones. Current forecast models predict that in western zones of the forecast region, snowfall amounts may exceed 50 cm.

Mon - trace amounts of snow   Winds E to  30 km/hr Freezing level 1200 m.

Tues- up to 20 cm of snow  Winds S to 50 km/hr Freezing level 1500 to 1600 m.

Wed- up to 50 cm of snow and some rain  Winds SW to 40 km/hr Freezing level 1500 down to 400 m. 

 

Prepared by Jesse Percival

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Important Notice

This bulletin covers the mountainous region of Vancouver Island from the Mt. Cain Ski Area in the North to the Beaufort range to the South including the mountains of Strathcona Provincial Park.

This is a regional forecast and significant variation may exist within the forecast area. The information and danger ratings are intended as a trip planning aid for recreational, backcountry users of avalanche terrain; they are not meant to be used as the sole factor in determining the avalanche danger presented by a specific slope.

Always include local weather, snowpack and avalanche observations in your decision to travel in avalanche terrain. Observations and experience may lead to different conclusions from what is reported or recommended. See disclaimer for further details. The technical data used to produce these bulletins is obtained from a variety of sources, including local ski areas and remote weather resources.