Subject: March 28, 2005 Canadian Avalanche Centre PAF South Columbia Region Forecast of avalanche danger beginning Monday, March 28, 2005: Day:\Monday p.m.\Tuesday\Wednesday Alpine:\Considerable\Considerable\Moderate Treeline:\Moderate\Moderate\Moderate Below Treeline:\Low\Low\Low Travel Advisory: A warm and moist storm deposited between 20 and 40 cm of snow over the weekend. Warm temperatures on Sunday moistened the snow surface to at least 2000m, so if you want cold dry snow you will need to travel high into the alpine. As usual this is where the most significant avalanche concerns are. On Monday we received reports of whumpfs, which suggests that the new snow is taking its time to stick to the old snow surface and in steep terrain you may easily trigger an avalanche. We don^Òt expect these conditions to last very long, but be suspicious of steep high elevation slopes for the next few days. Another concern is many slopes that face the sun will probably slide when they are affected by the intense solar radiation from the sun. Riding on lower angle terrain and avoiding steep slopes that face the sun will significantly reduce your risk to avalanches. Avalanches: A number of naturally triggered and human triggered slab avalanches were reported over the weekend. We expect the activity to taper off, but there are still a few surprises out there. Snowpack: Warm temperatures are causing the storm snow instabilities within the new snow to rapidly strengthen on Monday and Tuesday. The bond of the new snow to the old surfaces is taking longer, especially on north aspects. Some observers have reported a weak bond with old suncrusts. Weather: Unsettled weather on Monday and Tuesday will bring a mix of sun, snow and clouds. Expect it all. The freezing level will stay between 1500 and 1700m dropping to the valley bottoms each evening. A ridge of high pressure building on Tuesday afternoon will amplify through Wednesday giving a break in the weather until Thursday or Friday when the next storm is expected. Kootenay Boundary Region Forecast of avalanche danger beginning Monday, March 28, 2005: Day:\Monday p.m.\Tuesday\Wednesday Alpine:\Considerable\Considerable\Moderate Treeline:\Considerable\Moderate\Moderate Below Treeline:\Moderate\Low\Low Travel Advisory: It appears that Mother Nature is attempting to play catch up for an unusually dry and warm El Nino winter. Storm snow amounts are impressive by this winter^Òs standards ranging from 30 to 60 cm and it is continuing to snow at treeline and above on Monday. On Tuesday and Wednesday natural avalanches are possible on steep slopes that face the sun. On all other aspects it will become more difficult to trigger a slide, but when traveling on high elevation slopes watch out for soft windslabs just below ridgelines and stay highly suspicious of very steep slopes. Give the storm snow some time to stabilize. Avalanches: A natural avalanche cycle occurred on Sunday up to size 3.0. At high alpine elevations triggering an avalanche on a steep slope won^Òt be very difficult on Tuesday. Snowpack: Lots of snow fell during the past 48 hours. Unstable storm snow layers are present at 20 cm and 30 cm below the snow surface and they are quickly strengthening. The storm snow appears to be bonding well to the old snow surfaces, but reports of instabilities on old crusts remains a concern in similar situations in other forecast regions. Soft winds slabs 30 to 50 cm thick are reported on lee slopes in the alpine. Weather: Periods of heavy snowfall will continue Monday from Nelson south to the US border due instability in the atmosphere and moderate southwesterly winds causing an orographic boost to the precipitation. The rain snowline will be around 1500m. Unsettled weather on Tuesday may bring periods of snowfall above 1700m. On Wednesday and Thursday expect a brief break in the weather before another storm hits the area on Friday. Issued by: gj