Southern San Juan

A large winter storm begins to impact the Southern Mountains on Monday lasting through Wednesday. Expect the avalanche danger to rise quickly as heavy snow and strong winds build dangerous slabs of snow, and overwhelm weak snow layers.

Wet, heavy snowfall on Monday will quickly build shallow slabs of snow on top of various old snow surfaces. Strong southwest winds will drift the new snow into thicker slabs on leeward slopes above treeline. Avalanches in the new snow could break deeper if triggered from a shallower area of the slope where older, weak snow layers are closer to the surface. Cracking in the snow surface is an indicator of unstable snow below you. Avoid steeper areas above treeline if you notice the snow surface transition from soft to stiff, or where you see smooth, rounded pillows of snow.