Avalanche warning issued for San Juan Mountains

A large, rider-triggered slide that broke when approaching the flank of a wind-drifted area while ascending the slope. This slide occurred Feb. 15 in the north San Juan Mountains and broke at the new/old snow interface. (Courtesy Colorado Avalanche Information Center)
Up to 3 feet of fresh snow expected; storm is fueled by cold air from the northwest and moisture from south

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.”

A natural avalanche on Gibbs Peak, a northeast-facing slope below the tree line in the La Plata Mountains. The slide likely ran on Feb. 15 and broke at the new/ old snow interface. (Courtesy Chris Bilbrey)

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