TODAY...CLOUDY. CHANCE OF SNOW IN THE MORNING. HIGHS AROUND 42. LIGHT WINDS BECOMING SOUTHEAST 10 MPH IN THE AFTERNOON.

TONIGHT...CLOUDY. LOWS AROUND 32. SOUTHEAST WIND 10 TO 15 MPH.

TUESDAY...MOSTLY CLOUDY. HIGHS AROUND 44. NORTH WIND 10 TO
15 MPH.

With not much precip in the last two weeks, no serious precip in todays forecast, and cool temperatures, avalanche danger is LOW at this time.

If we see much sun today be cautious on south facing slopes later in the day as the heat of the sun comes into affect.

Point release avalanches are possible on those aspects during the diurnal fluctuation of the day.

Enjoy a Juneau Spring Day!!!

Sun Crusts:

A frozen sun crust sometimes forms a hard bed surface for future avalanches to run upon. However, a sun crust typically has a fairly rough texture when compared to the more slippery rain crust, and snow deposited on the crust tends to bond better than you would imagine. However, a sun crust forms a strong mechanical discontinuity in the snowpack, which tends to concentrate any shear deformation within the snowpack to the layers just above and below the sun crust. But probably more important, crusts tend to concentrate temperature gradients above and below them and they can grow a thin and almost invisible layer of weak faceted snow. This probably accounts for most of the avalanches that occur on sun crusts, especially in non-maritime climates. Also, surface hoar that grows on top of a sun crust can be a very nasty weak layer.

Sun crusts, of course, form only on sunny slopes and not at all on the shady ones. So we find them mostly on southeast, south, southwest and west facing slopes at mid latitudes in the Northern Hemisphere (and conversely forms more uniformly on all aspects in tropical and arctic latitudes). Instabilities associated with sun crusts usually stabilize fairly quickly after a storm, depending on temperature, except if faceted snow has grown around the sun crust or surface hoar has grown on top of the crust, it can produce much more persistent avalanche activity.

Hot Tip:

When new snow falls on a sun crust, it's important to check out whether the sun crust is wet or frozen when the snow starts. If it's wet, the new snow will stick to it and you most likely won't have any immediate avalanche problem, but if the crust is frozen, then the new snow does not tend to bond very well.