An avalanche warning is in effect for the southern San Juan Mountains until 11:45 p.m. Wednesday, according to the Colorado Avalanche Information Center.

For Wednesday, the risk is rated at “high,” or Level 4 out of five on the avalanche danger scale, for areas near or above tree line. Below tree line is rated at “considerable,” Level 3 out of five.

For Thursday, the danger is rated at “considerable” for below, near and above tree line.

“Very dangerous avalanche conditions will develop by late Wednesday afternoon and continue through Thursday,” the warning states. “Avalanches will be very easy to trigger. Travel in avalanche terrain is not recommended during this time period.”

The area of increased danger includes south of Red Mountain Pass, the La Plata Mountains, areas around Wolf Creek Pass and the South San Juan Wilderness.

A major storm Tuesday night will produce 2 to 3 feet of new snow in the high country by Thursday morning, the CAIC forecast states.

It is fueled by deep trough of cold air pulled from the northwest by the jet stream that will meet up with a low pressure system holding abundant moisture from the Gulf of Mexico.

Strong southwesterly winds arrive with the storm, and the ongoing snowfall and wind will create worsening conditions as Wednesday progresses.

The new snow and winds will likely generate slab avalanches.

“Expect rider-triggered avalanches to be likely,” the warning states. “With such strong winds arriving at the same time that snow is falling, expect wind-deposited snow further down slopes than is typical, including more open areas below the tree line.”

jmimiaga@the-journal.com