 double-double seeking, snow-chasing, short-cutting, vertical feet collector
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Posted - 03/08/2004 : 7:45 PM
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March 8, 2004
This Forecast Sponsored by The Canadian Avalanche Foundation
South Coast Region
Weather: The worst of the storm has passed, with the majority of moisture now going up to the North Coast. With this system came 30-100 cm of new snow and strong southerly winds. Temperatures continue to rise, and as of noon Monday was over +10 degrees at 1500 m. Light precipitation and moderate southwest winds will continue overnight on Monday. Thankfully, things will dry out starting Tuesday with little or no precipitation on the horizon until later in the week. Freezing levels will drop from near 2800 m on Monday to 1800 m on Tuesday and continued cooling is forecast Wednesday. This should give you a chance to dry your gumboots.
Snowpack: The new snow from the weekend has buried a number weak layers including several surface hoar layers and sun crusts. The warm temperatures, heavy snowfall and strong southwest winds have formed this snow into dangerous windslabs on north through east aspects. Unstable slabs may be up to 150 cm thick in wind loaded areas. Stability tests tell us little right now in comparison to the reports of cracking, whumpfing and remotely triggered avalanches. These observations clearly illustrate an unstable upper snowpack.
Avalanche Activity: A province wide natural avalanche cycle occurred throughout the region on Sunday and Monday, with numerous large avalanches from all aspects and elevations.
Forecast of Avalanche Danger Up To Wednesday Evening (March 10, 2004)
Alpine – High
Treeline – High
Below Treeline – Considerable
Travel Advisory: With very warm temperatures avalanche activity will be slow to subside. In the long run the warm temperatures may help rid the snowpack of weak layers and we’ll end up with a more stable snowpack. For now, the avalanche danger remains High at treeline and above until mother nature runs it’s course and the snowpack adjusts to the warm temperatures. Travel in avalanche terrain should be limited to very safe terrain.
North Columbia Region
Weather: Breathe a sigh of relief and wring out your mittens now that the wet and wild storm system has moved northward. Thirty to 80 cm of storm snow fell up high, accompanied by strong southwest winds and rapidly rising temperatures. The freezing level will rise to 2600 m on Monday before dropping sharply down to 1000 m on Tuesday and remaining there for Wednesday. Ten to 15 cm of snow is forecast at higher elevations in northern parts of the region on Monday evening, and little or no precipitation for Tuesday and Wednesday. Southwest winds should increase again to 40-60 km/h in the alpine, and not ease off much until Wednesday.
Snowpack: All reports were in agreement that we have a very unstable upper snowpack. Up to 80 cm of storm snow is very reactive to human triggers, and the number of reports of huge whumpfs, cracking and human triggered avalanches are warning enough. The failure layer of avalanches is both on the surface hoar layer from early March and the deeper February 14 layer.
Avalanche Activity: The number of reports on Sunday of skier triggered and natural avalanches was alarming. Many of these occurred on terrain as gentle as 30 degrees, and several were triggered remotely from even gentler terrain. As natural activity subsides, the likelihood of human triggered avalanches will increase.
Forecast of Avalanche Danger Up To Wednesday Evening (March 10, 2004)
Alpine – High
Treeline – High
Below Treeline – Considerable
Travel Advisory: The warm temperatures will continue to consolidate the recent storm snow slab, and the potential to trigger an avalanche will continue to rise for the time being. You’ll need to choose your terrain very wisely over the next few days considering that it is possible to trigger avalanches even from flat terrain.
March 8, 2004
This Forecast Sponsored by The Canadian Avalanche Foundation
South Columbia Region
Weather: The intense weather system that stormed through BC on the weekend has mostly run out of gas and headed further north. Storm snowfall amounts varied from 15 cm in the Purcells up to 50 cm in the wetter western slopes. Winds became strong southwest and temperatures are still rising and expected to top 2600 m on Monday before dropping back down to 1500 m on Tuesday. Additional light precipitation is expected overnight Monday, but things should be mostly dry and cooler for Tuesday and Wednesday. Alpine winds are forecast at 30 km/h from the southwest until Tuesday, then ease off and come from the northwest on Wednesday.
Snowpack: Moderate to strong winds have transported up to 50 cm of storm snow to north and east facing slopes, continuing to build slabs overtop a series of weak layers. Slabs will continue to settle with the very warm temperatures, so expect this slab to become stiffer and easier to trigger over the next few days. Stiffer slabs are associated with large propagation of avalanches, especially when the slab overlies already weak surface hoar layers —one just below the storm snow and two older layers around 50-100 cm deep.
Avalanche Activity: A widespread natural avalanche cycle continued on Monday, and will continue with the very warm temperatures. One observer reported a Size 3 natural near Sandon propagating 1 km across a slope. Several reports of small skier controlled avalanches occurred on surface hoar layers buried 30-70 cm deep.
Forecast of Avalanche Danger Up To Monday Evening (March 8, 2004)
Alpine – High
Treeline – High
Below Treeline – Considerable
Travel Advisory: As the natural avalanche cycle starts to subside over the next couple of days, the potential to trigger an avalanche will increase. With touchy conditions such as this, avalanches won’t care if you’re a sledder or shredder, since even small stresses could trigger avalanches right now.
Kootenay Boundary Region
Weather: The intense weather system that stormed through BC on the weekend has run out of gas and headed further north. Storm snowfall amounts were 30-50 cm in the wetter areas, but only 10-15 cm in the dryer mountain areas around Rossland and Cranbrook. Winds became strong southwest and temperatures are still rising and should top 2600 m on Monday before falling to 1500 m on Tuesday. Additional light precipitation is expected overnight Monday, but Tuesday and Wednesday should be mostly dry and cooler. Winds are forecast at 30 km/h from the southwest until Tuesday, becoming light from the northwest on Wednesday.
Snowpack: Another 30-50 cm of snow has added additional stress on top of several buried surface hoar layers. Unusually warm temperatures right into the alpine are causing slabs to settle and become stiffer. The snowpack is responding to this stress with a natural avalanche cycle, and seen from shooting cracks from skis. Strong winds transported snow to north through east facing slopes, so this is where the danger will be highest.
Avalanche Activity: A widespread natural avalanche cycle occurred on Sunday and Monday and will likely continue at least until Tuesday. One report came in of a Size 4 avalanche propagating almost 1 km across a slope and close to 1 m deep, likely reaching down to the Feb. 14 surface hoar layer.
Forecast of Avalanche Danger Up To Monday Evening (March 8, 2004)
Alpine – High
Treeline – High
Below Treeline – Considerable
Travel Advisory: There is no question that the snowpack is very unstable right now, and that good route finding skills are required to travel safely in avalanche terrain. Backcountry users who lack these skills should wait until the snowpack improves and avalanche danger decreases. Even flat areas can be dangerous right now considering large avalanches may run to valley bottoms and the possibility of remotely triggering an avalanche.
March 8, 2004
This Forecast Sponsored by The Canadian Avalanche Foundation
South Rockies Region
Weather: An increasingly warm and wet weather system passed through on the weekend, laying down up to 15 cm of snow in the mountains. Winds were moderate to strong from the southwest, but have mostly died off now. Most importantly, the temperatures soared on Monday, reaching +10 degrees in the valleys, with the freezing level approaching 2800 m. Light precipitation will continue through Tuesday, but the overall trend is for dryer conditions on Wednesday. The freezing level should fall back down to around 1500 m by Wednesday.
Snowpack: The storm snow came in wet and heavy, building up even thicker slabs on top of a number of weak layers. These include a buried crust on south facing slopes and surface hoar on northerly aspects. Deeper surface hoar layers are now buried up to 1 m below the surface, except in shallow snowpack areas where they are closer to the surface. The upper 1 m of the snowpack is unstable and human triggered avalanches are likely.
Avalanche Activity: As of late Monday afternoon, a widespread natural avalanche cycle continues in the region. Numerous natural avalanches were reported mostly on southeast to northeast facing slopes near treeline. Skier controlled avalanches up to Size 2 were reported starting on surface hoar buried 65 cm deep.
Forecast of Avalanche Danger Up To Monday Evening (March 8, 2004)
Alpine – High
Treeline – High
Below Treeline – Considerable
Travel Advisory: In the last forecast we described the recipe for avalanches: lots of new snow, strong winds, weak layers close to the surface, and rising temperatures. All ingredients are now in place so it’s not surprising that we’re seeing an extensive avalanche cycle in the region. Mother nature will need some time to take care of matters. This may take a few days so, until conditions improve, you should limit yourself to very conservative terrain, particularly slopes less than 30 degrees. Remember that with the current conditions it’s possible to trigger an avalanche from even gentle terrain and that natural avalanches may run down into the valley bottoms. |
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March 8 Canadian Avalanche Association PAB
