It's full on spring and I've stopped issuing regular forecasts but that doesn't mean the end of avalanches. Changing weather including new snow, wind, warm weather, and nights without a refreeze can significantly affect the snowpack causing a change in avalanche conditions. These are the problems you are going to want to look out for:
Wet snow: With a strong sun and warm temperatures, wet snow avalanches are often the primary concern in the spring. Both loose wet, and wet slab avalanches are possible this time of year. As the day heats up the snow becomes saturated as it begins to melt and water runs through the snowpack. Work with the sun and get off of steep slopes as they become wet and sloppy. Signs of instability include roller balls, pinwheels, and loose snow point releases or sluffs. Several nights without a refreeze contribute greatly to snow instability making wet slab avalanches more likely. Pay attention to overnight low temperatures, and if the snow feels punchy and unsupportable, even first thing in the morning, it's not a good to day to be in the mountains.
New Snow: Spring storms can bring significant amounts of new snow to the mountains, and anytime we get about 6" or more we have to start looking at the possbility for avalanches wiithin the new snow. New snow avalanches can occurr as loose, dry sluffs that run on the underlying slick surface, or as soft, cohesive slabs that have bonded poorly. Even small sluffs can be problematic in the wrong place as they could sweep you off your feet and carry you into trees or over a cliff. Soft slabs, even shallow ones can pack even more of a punch. Signs of instability include cracking in the snow surface and other avalanches.
Wind Drifted Snow: Wind moves snow around creating unstable drifts on the leeward sides of ridge crests and terrain features. Snow starts moving with wind speeds above 15 mph, and the stronger the winds, the more snow gets moved. Wind drifts are recognizable by their smooth, rounded appearance and often feel hollow undernearth. Wind slabs can be soft or hard and they tend to stabilize after a few days, but they can sometimes linger for a week or even longer. And like loose snow sluffs, even a shallow wind slab can be problematic in consequential terrain. Learn to recognize and avoid steep, wind drifted slopes.
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