Dashboard Regions Weather Stations Radar Alerts Glossary
Contact About
Log In

Register for an account and never miss a forecast again!

Register

Avalanche Forecast

Archived

Mar 14th, 2014–Mar 15th, 2014

Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches possible, human triggered probable.
Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches unlikely, human triggered possible.

Regions

Olympics.

Avalanche danger should increase during the day on Saturday. Watch for sensitive wind slab on lee easterly aspects formed on Friday and for new shallow storm slab later Saturday afternoon. Wet loose concerns should be the primary concern at lower and mid elevations with a transition to light rain during the day. The avalanche danger should increase further Saturday night. 

Detailed Forecast

A warm front should stay draped over the US/Canadian border Saturday, producing moderate precipitation at rapidly increasing snow levels for the Olympics on Saturday. 

Loose wet avalanches will be the primary concern on Saturday as a transition to rain loads new snowfall received on Friday or early Saturday in the Olympics. Wet loose avalanches are becoming more likely if you see pinwheels or initial small natural wet loose releases. Moderate westerly winds on Friday may have built sensitive wind slab on lee easterly aspects in this region near and above treeline. Shallow new storm slab that layers denser snow on top of less dense snow from Saturday morning may be concern at higher elevations by Saturday afternoon. Use caution on Saturday and expect increasing avalanche danger during the day.  

Also due to the rapid warming Saturday, expect cornices to be sensitive Saturday and give them a wide berth. 

Snowpack Discussion

Over the past month two major storm cycles moved across the Pacific Northwest. The most recent week long storm cycle occurred in early March and wound down last Sunday. This storm cycle produced similar water equivalents as the February cycle; about 4 inches of water and 2 feet of snow at Hurricane Ridge. This cycle was warmer and featured mainly wet snow and rain leading to several natural avalanche cycles during the first week of March. Average freezing levels have been roughly 2000-3000 feet higher thus far in March versus February! 

NWAC observers Tyler and Katie Reid last Friday at Hurricane reported wet and saturated upper snow pack layers and numerous wet loose avalanches to size 2. Warming effects had penetrated quite deeply into upper snowpack layers. Here is a video from Tyler and Katy at Hurricane from last Friday. Warm wet weather last weekend caused wet snow conditions and many wet loose avalanches at Hurricane with several cornice collapses as well as reported by NWAC observer Katy Reid on Sunday.

Several large and destructive wet slab avalanches released down to old facet/crust combo from earlier this winter naturally and with explosives early last week over the west slopes of the Cascades. It is unknown if any avalanches this large occurred in the Olympics. 

A NPS ranger reported a few inches of new snow over a firm crust late Friday morning at Hurricane Ridge.  A few more inches of snow likely accumulated during the day down to around 4000 feet with some wind transported snow likely near treeline due to moderate westerly winds.

Problems

Loose Wet

Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.

Storm Slabs

Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.