Snowpack Summary published on April 27, 2019 @ 7:29 am
Issued by Ryan Lewthwaite -

bottom line:

There hasn't been a solid overnight refreeze in six days, leaving slopes slushy, unconsolidated & ripe for Loose Wet or Cornice Fall avalanches. Consider avoiding steep aspects facing SE-S-SW as they will hold the potential for avalanches even during the morning hours. Please enjoy our last weekend of snowmobiling as April 28 will be the last day of it in the BWRA. Plowing has reached the Leavitt Lake Rd junction & today we share the road with anglers.

Avalanche Character 1: Loose Wet
Loose Wet avalanches occur when water is running through the snowpack, and release at or below the trigger point. Avoid very steep slopes and terrain traps such as cliffs, gullies, or tree wells. Exit avalanche terrain when you see pinwheels, roller balls, a slushy surface, or during rain-on-snow events.

Deep & sometimes slow-moving, these near slush avalanches will be likely on all aspects & elevations. Expect slopes facing SE-S-SW to be the most reactive to human triggering. Very "punchy" conditions exist below 8500' on these aspects, & finding subsurface objects is very easy. 

Avalanche Character 2: Cornice
Cornice Fall avalanches are caused by a release of overhanging, wind drifted snow. Cornices form on lee and cross-loaded ridges, sub-ridges, and sharp convexities. They are easiest to trigger during periods of rapid growth from wind drifting, rapid warming, or during rain-on-snow events. Cornices may break farther back onto flatter areas than expected.

Cornices are dripping & beginning to slump off. Southern exposed Cornices are most prone to failing, some have noticable cracks forming where separation in emminent. Cornices have been falling & entraining Loose Wet avalanches of D2 proportions.

Snowpack Discussion

Full-on spring conditions exist in the BWRA with Loose Wet & Cornice avalanches appearing regularly. It is visible that the slopes are beginning to creep & glide with gravity. Slopes that look lumpy or as if they have stretch marks, should be avoided. The wet unconsolidated snow is becoming very unstable on SE-S-SW aspects, especially below 8500'. It is now very easy to ski & track penetrate the snow to depths over 10", with the potential to hit subsurface objects or start a slow-moving Wet avalanche. Our snowpack is at 0C to depths over one meter deep.

recent observations

~4/26 Cornice fall & Loose Wet avalanches observed on South aspects, some as combo failures. Human triggering is very likely.

~4/23 Virginia Lakes Rd Open. Timing the conditions is key; too early & its firm & too late its sloppy.

CURRENT CONDITIONS Weather observations from Sonora Pass
0600 temperature: 38 deg. F.
Max. temperature in the last 24 hours: 55 deg. F.
Average wind direction during the last 24 hours: Southwest
Average wind speed during the last 24 hours: Light mph
Maximum wind gust in the last 24 hours: Moderate mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 73 inches

Today will continue to be warm & pleasant with no precipitation. The rate of snow melting has been around 2" per day. Winds have been light to calm with no blowing snow. Sunday has a potential for showers, likely rain up to 9K. I would be surprised to see any snow accumulations, showers will be spotty. Near normal temperatures will return with this upper level low pressure mass.

Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 8000 ft. to 10000 ft.
  Saturday Saturday Night Sunday
Weather: Sunny Partly cloudy then becoming clear. Sunny with increasing clouds & a slight chance for showers later.
Temperatures: 52 to 62 deg. F. 30 to 36 deg. F. 49 to 59 deg. F.
Wind direction: Southwest Southwest Southwest
Wind speed: 15 mph; gusts to 30 mph later 15 to 20 mph; gusts to 35 mph 15 mph; gusts to 35 mph
Expected snowfall: 0 in. 0 in. 0 in.
For above 10000 ft.
  Saturday Saturday Night Sunday
Weather: Sunny Partly cloudy. Partly cloudy with a slight chance for afternoon showers. Snow Level 9000'
Temperatures: 41 to 51 deg. F. 25 to 30 deg. F. 39 to 48 deg. F.
Wind direction: Southwest Southwest Southwest
Wind speed: 15 to 20 mph; gusts to 30 mph 15 to 30 mph; gusts to 35 mph increasing to 45 mph late 20 to 30 mph; gusts to 45 mph decreasing to 15 to 20 mph; gusts to 30 mph later
Expected snowfall: 0 in. 0 in. 0 in.

This snowpack summary applies only to backcountry areas in the Bridgeport Winter Recreation Area. Click here for a map of the area. This snowpack summary describes general avalanche conditions and local variations always occur. This snowpack summary expires in 48 hours unless otherwise noted. The information in this snowpack summary is provided by the USDA Forest Service who is solely responsible for its content.