... STRONG WIND THROUGH MONDAY MORNING ...

TODAY ... SUNNY ... LOCALLY WINDY. HIGHS 29 TO 35. NEAR DOWNTOWN JUNEAU AND DOUGLAS AND INTERIOR PASSES ... NORTHEAST WIND 15 TO 25 MPH WITH GUSTS UP TO 50 MPH. ELSEWHERE ... NORTHEAST WIND 10 TO 20 MPH.

TONIGHT ... CLEAR ... COLDER. LOCALLY WINDY. LOWS 10 TO 18 ... EXCEPT AROUND 7 ABOVE IN WIND SHELTERED AREAS. NORTHEAST WIND 10 TO 25 MPH. WIND GUSTS TO 45 MPH NEAR DOWNTOWN JUNEAU AND DOUGLAS AND INTERIOR PASSES.

No new precip. Winds have held steady out of the SE, though they have picked up to alomst 40kts at the Tram. Temps are still dropping slowly but steadily, down to almost -9c at the Tram. Still not much snow left for wind transport at ridgetop levels.

Surface hoar is forming in wind sheltered areas with these lower temps. The Crust/Facet combo responsible for our last avalanche cycle still persists in the alpine on both the Mainland and on Douglas.

Even though the Hazard is at Low for the Urban zones, there remains a chance of warm, wet, point releases above the Flume and Perseverance area which still have the potential to step down into either wind slabs or the faceted layer just above the big Melt-Freeze Crust.

Hazard is LOW today: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features. Natural and human-triggered avalanches unlikely. Small avalanches in isolated areas or extreme terrain. Normal caution is advised.

Human triggered slides are still possible in backcountry locations, and likely in the few wind sheltered areas above treeline. If you are sledding or skiing keep that in mind and travel accordingly.

SPATIAL VARIABILITY

Local Forecaster Ron Simenhois wrote a great column on spatial variability last year. Selections from it are below:

Spatial variability can be very obvious. For instance, the snow in a forested area is very different than in the openings between the tree-covered areas. It can also exist on what seems to be very uniform slopes. In 2004, Cam Campbell and Bruce Jamieson presented a study that looked at Rutschblock test results in avalanche start zones. One of the slopes they tested was a uniform slope, all their tests failed on the same weak layer; however, test results varied from ?almost certain to trigger an avalanche? (score 2) to ?almost impossible to trigger an avalanche? (score 6) within less than 10 feet.

Depending on its scale and the avalanche problem we deal with, spatial variability can be a friend or an enemy. When our main concerns are large avalanches, spatial variability can limit the size of an avalanche to a relatively small release area.

However, when we ski a slope where small avalanches can be deadly, relying on snowpack information from one area to apply to the entire slope can be a bad call.

Regardless if it is a friend or enemy, spatial variability is a big deal for avalanche folks. It means uncertainty and we like be as certain as possible when we look for our own and for other people?s safety.

Weak layers that are in one pit sometimes do not exist in a different pit only 30 to 45 feet away and vice versa. In other words, the snowpack is spatially variable. Which is what we are seeing right now.

A week of strong winds has stripped some areas while loading others. This has futher had the effect of insulating a buried faceted layer in some areas while allowing it to break down in others. There is a lot of spatial variability going on out there right now, and the consequences for relying on only one data point, or one avalanche forecast can be high.