Friday afternoon will be the best chance for wet snow instabilities, though the hard freeze overnight should delay snow surface warming and limit the depth of surface instabilities. Increasing winds and cloud cover on Saturday afternoon, and cooler, unsettled weather into mid-next week should mitigate wet snow instabilities for the next few days.
Pockets of Wind Slab may develop near and above treeline from the expected snowfall, cold temps, and windy conditions on Sunday, and with the continued showers and cold temps Monday night into Tuesday.
*This avalanche problem is expected to develop outside the normal forecast period for this Snowpack Summary and will NOT be confirmed with field observations next week.
Special Announcement: This will be the final Snowpack Summary issued for the 2014-2015 season. Thank you to all for your interest, participation, and support! We have had a great season despite low snow conditions and we are already looking forward to next season. We will continue to post updates on the BAC website, so stay tuned, have a great summer, and think snow!
The Bottom Line: With hard overnight freezes and cool daytime temps, snowpack stability in the BWRA has been very good over the past three days. Minor surface Loose Wet snow instabilities may develop today with warmer temps, light winds, and sunny skies. Cooler, unsettled weather starting Saturday will minimize wet snow instabilities through the middle of next week. Up to 6" of snow possible on Sunday with cold air and windy conditions may create pockets of Wind Slab near and above treeline.
Discussion: The snowpack in the BWRA has been through almost an entire season of melt/freeze cycling...free water drainage is well established. As we enter late Spring / early Summer, continue to watch for wet snow instabilities. Weather conditions that contribute to snow surface warming and free water percolation in the snowpack include: warm daytime AND nighttime temps; sunny skies and intense solar radiation; continuous cloud cover that re-radiates longwave energy into the snowpack and ground; absence of wind to cool the snow surface.
Signs that the snowpack is becoming unstable due to warming: recent wet snow avalanches on similar aspects and elevations; postholing above your boot tops without skis; anytime you sink through wet surface snow to weak layers below ON YOUR SKIS; rapid increase in roller-ball and pinwheel activity.
Cold, dry faceted layers may persist above 10,500' for several weeks. Be alert for rapid warming (especially heavy rain) and/or significant loading events (new snow, windloading, rain) on upper elevation starting zones and pockets of cold snow on shaded aspects and near rocky outcrops.
Ski tours below 10,000' this week showed minimal warming of the snow surface - crusts remained intact through the day due to moderate to high winds, intermittent cloud cover, cold overnight temps (high teens, low twenties), and cool daytime temps (high thirties, low forties). Digging revealed multiple crust layers, moist slabs, and water ice formations throughout the snowpack. No propensity for failure or propagation was observed.
Warm temps, sunny skies, and light winds today give way to increasing winds and cloud cover Saturday afternoon and passage of a cold front on Sunday. The heaviest snow showers from this cold storm are expected on Sunday afternoon, with 6" of snow possible at higher elevations. Low pressure and unsettled weather is expected through the middle of next week; continued snow showers are possible Tuesday night into Wednesday.
This snowpack summary applies only to backcountry areas in the Bridgeport Winter Recreation Area. Click here for a map of the area. This snowpack summary describes general avalanche conditions and local variations always occur. This snowpack summary expires in 48 hours unless otherwise noted. The information in this snowpack summary is provided by the USDA Forest Service who is solely responsible for its content.
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