Avoid steep slopes that are getting baked in the sun, and use extra caution in thin, rocky start zones.
Expect variable snowpack conditions as we transition from winter to spring.
During periods of daytime warming and sunshine, expect the surface snow to be unstable on slopes that face the sun.
A wet storm added a lot of moisture and heat to the upper snowpack earlier this week.
If you see signs of loose wet instability, like snow that feels like a slurpy, or clumps up and pinwheels down a slope, move to less steep and more shaded terrain.
The base of the snowpack remains weak. Avoid thin, rocky start zones and shallow areas with variable snowpack depths.
On Thursday, our South Rockies field team was out in the Mear Lake area, and they saw numerous, small (size 1-1.5), naturally triggered wet loose avalanches on steep, sunny slopes at treeline and above. See their MIN (Mountain Information Network) post here for more details.
Avalanches from earlier in the week are being reported as visibility improves, and people venture into the backcountry after the storm. As expected, there appears to have been a widespread avalanche cycle, with numerous large (size 2) and some larger (size 3) avalanches. Mostly storm slabs in the alpine, and wet loose at treeline and below.
A few avalanches likely started as storm slabs in the alpine, or just below a ridge, picked up loose wet snow, kept moving over dirt in some places, and ran down well into treeline, covering lower elevation hiking trails or forest roads.
If you head out in the backcountry, let us know what you are seeing by submitting a report to the Mountain Information Network.
Dynamic spring weather has resulted in variable snow surface conditions. A wet storm earlier in the week soaked the upper snowpack. Cold overnight temperatures have turned this moist snow into a frozen crust, except in areas where dry snow covered and insulated it.
The mid snowpack is generally settled and strong, except in areas with snow depths less than 150 cm. In these lower snow areas, the mid-pack is likely weaker and more faceted.
Below treeline, expect to find moist or refrozen surfaces, and a shrinking snowpack that is isothermal during the heat of the day.
The lower snowpack includes a layer of large, weak facets and/or depth hoar crystals.
Friday Night
Mostly clear. No new snow expected. Freezing level variable through the region, valley bottom to 1500 m. Treeline low between -3°C and -8°C. Light southwest ridgetop wind.
Saturday
Mostly sunny. No new snow expected. Freezing level rising to 2100 m. Treeline high around 1°C. Light southwest ridgetop wind.
Sunday
Mostly cloudy. 0-5 cm of snow expected in the alpine. Freezing level at 1500 m overnight, rising to 2000 m. Light southwest ridgetop wind, trending to strong at high elevations.
Monday
Cloudy overnight with 5-10 cm of snow expected in the western half of the forecast area. Mostly sunny through the day. Snow/rain line at valley bottom overnight, daytime treeline high around -2°C.
More details can be found in the Mountain Weather Forecast.
