Avalanche Concerns Continue in High Country
Lake County Sees Spring Snow
Once the calendar turns to May in the Colorado high country, folks are ready to talk about something other than snow, especially after this winter. Of course, this week if you live in Leadville Today you saw some snow on the ground every morning to mark this first week in May. And on Friday mornings like this one, it might be tempting to simply not discuss the unwanted houseguest that Old Man Winter has become, except there are some updates from the Colorado Avalanche Information Center (CAIC) that were issued late Thursday, May 9 that are important to be aware of as this latest spring snow system is expected to hang around for another 24 hours. Hopefully, meteorologists are right about the Mother’s Day forecast: sunshine and blue skies, with a high of 50!
Highlights from CAIC: Thu, May 9, 2019 at 3:11 p.m.
Issued by: Spencer Logan
Snowfall will add avalanche concerns to the top of the snowpack. Expect to easily trigger avalanches on steep slopes with more than about 6 inches of snow. Areas of the Sawatch Range south of Independence Pass will have a foot and a half of new snow by Friday morning, making avalanches large and dangerous. Other spots could see decent snow accumulation from snow showers. Deceptively soft slab avalanches may break in the storm snow. Moderate winds and swirly gusts will drift snow into gullies, couloirs, and below cornices. It will be easy to trigger avalanches in the drifted snow. We have seen a rash of triggered avalanches after every recent storm. As folks venture into steep and cliffy terrain, even small avalanches have large consequences.
Avalanches in the new snow have the potential to pull out weak layers deeper in the old snow, or to entrain unconsolidated wet snow near and below treeline. Observers have reported a few avalanches gouging down over the past week, mostly on the northeast, east, and southeast aspects. Expect to see more. The new snow will also take slopes that previously avalanched and push them closer to the breaking point. Starting zones that ran in early March are now refilled with enough snow to avalanche again.
When the sun breaks through the clouds, fresh snow will quickly turn wet. Expect to see loose avalanches running from trees, rocks, and cornices. They could entrain lots or all of the recent snow.
Thursday afternoon (5/09/19) and evening brings another round of snow showers. The brunt of the moisture will hit the San Juan Mountains and the Sangre de Cristo Range. Enough moisture spills over those areas of the Central Mountains, particularly the Sawatch Range, could see some locally intense snow showers. Under the snow showers, accumulations could be 6 to 9 inches of snow by morning. Outside of the showers, expect a couple more inches of snow to accumulate. Snow showers continue through the day on Friday. It does not look like they will bring much additional snow. Any snow that does develop will be competing with gradually warming temperatures through the day. Showers dissipate by evening, with Friday night and Saturday looking relatively dry. Scattered afternoon snow showers are possible, though accumulating snow is not very likely.
Snowpack and Avalanche Discussion
Examine the bond between fresh snow and the old snow surface–it may be poor, and the new snow easily sheets off. Spots with more than about six inches of poorly bonded new snow can produce storm slab avalanches large enough to take you for a ride. Spongey old snow could bond to the new snow well. Expect lots of variation in the bond over short distances as you change elevation and aspect. Within the storm snow, look for areas of drifted snow. Moderate winds and swirly gusts will drift pockets of snow into gullies, couloirs, and below cornices. Stiffer or chalky feeling layers, or seeing cracking in the new snow, are indications to avoid steep slopes where you could trigger avalanches in the wind-drifted snow.
Avalanches in the new snow could trigger layers of older snow and result in big avalanches. Observers report a few large avalanches like this in the Northern and Central Mountains running since the end of April. The slides have been on the northeast, east, and southeast facing slopes. Most of these slides have started as loose avalanches or cornice fall, before pulling out the larger and deeper slabs. Near and below treeline, avalanches have broken on layers of wet snow avalanches. If you are unable to get out and enjoy the power, you could read about melt-layer recrystallization.
The new snow will also take slopes that previously avalanched and push them closer to the breaking point. Starting zones that ran in early March are now refilled with snow. The snow is relatively shallow and weak. It is now deep enough to form cohesive slabs, though, and the slopes are reloaded. The Star Mountain path in the Sawatch Range is a good example of these paths running again after a storm.
Loose avalanches will become frequent as the sun breaks through the clouds and temperatures warm up this weekend. If you are traveling in steep terrain, even a small wet avalanche can knock you off your feet and send you for a dangerous ride. You will know when the chance of triggering one of these avalanches is increasing when the surface snow gets wet and gloppy. Other indicators are rollerballs and small point releases running from steep terrain. Start early and get off of slopes before these conditions take effect. If you find yourself falling into wet unconsolidated snow, it is time to move to low angle or shady slopes.
Avalanche Debris Revealed on Highway 82
As the Colorado Department of Transportation (CDOT) crews continue to work on Highway 82, hoping to open Independence Pass by the traditional Memorial Day Weekend date, more and more snow slides have been revealed along the way on the Lake County side of the seasonal pass. In this video taken on May 1, 2019, two massive avalanches can be viewed, which ultimately crossed the roadway – twice – leaving behind measurable road damage and big debris fields. No word from CDOT officials about whether Indy Pass will open at the end of this month or what the plan is for road repair and clean-up.
The FoCAIC is a 501(c)3 non-profit organization that was created to financially support avalanche forecasting and
education throughout Colorado. We accomplish this through fundraising that includes grant writing, events,
individual fundraising, corporate partnerships, and our annual spring fundraising campaign. The FoCAIC has 3 full
time staff members that work out of home offices and from road throughout the winter. FoCAIC also has a small
Board of Directors that guides the mission of the organization and oversees the ED.