Good morning this is Sue Burak with the Inyo National Forest Eastern Sierra Avalanche Center with an avalanche advisory for Wednesday, February 18. If you are skiing on June or Mammoth Mountain today, please respect all ski closures and don't duck under the ropes. MOUNTAIN WEATHER In the last 24 hours, 4-10 inches of new snow fell in the mountains around Mammoth and June Lake. The next few days through Saturday are forecasted to be dry and mostly sunny. By the end of the week, daytime temperatures could be in the low 40s at the 8,000 ft elevation and in the close to 30F in the mountains above 10,000 ft. Night time lows will continue to be in the low to mid teens at all mountain locations. South winds will be light through the week. Winds will increase from the southwest on Saturday as the ridge moves to the east and a patter. A large low pressure system is building in the eastern Pacific. Any weather forecasts can and will change because there are 4 days before the low is supposed to reach the West Coast. Little is certain as to if, when and where the system will affect the area. SNOWPACK AND AVALANCHE DISCUSSION There are 2 big avalanche concerns today. The Mammoth Lakes Basin and the backcountry around June Lake have received several feet of new snow in the last few days. Strong southerly winds are responsible for the latest round of wind loading with west winds loading east slopes late Friday. Wind loading has occurred at all elevations in the mountains. Sensitive wind drifted snow and wind slabs are widespread above treeline and today it is likely a person could trigger a slab avalanche. Middle elevations in the trees and most glade skiing locations could also have tricky wind slabs in open areas and cross loaded gullies. Shooting cracks, collapsing and small natural avalanches on wind-loaded slopes are all signs of instability. The second important avalanche concern today is buried weak faceted snow. Ski patrol on June Mountain has triggered many large avalanches in the last two days, in terrain that has not been skied yet this year. Several large avalanches ran to the ground on faceted snow that formed in January. Wind loaded snow doubled the snowpack depth before the 4 ft crown released with a hand charge. A ski cut under Chair 1 at June Mountain triggered a large avalanche that ran on the January rain/ snow layer. Unusual avalanches occurring in areas never seen to slide are bold red flags yelling out that conditions are dangerous. Skiing or riding the lower Hemlocks and other very popular slopes on steep north facing slopes in the trees and glades will expose you to widespread dangerous avalanche conditions. These steep slopes have not been skied this year because of a shallow snowpack. Buried surface hoar that is easily seen in a snowpit is very uncommon here- surface hoar is a dangerous weak layer responsible for many avalanche fatalities in Utah, Colorado and Wyoming every winter. Skiers and riders here in the Sierra are not accustomed to buried weak snow that does not give any prior warning before an avalanche releases. Unstable wind loaded slopes give clear warnings of instability like whumpfing and cracking. Take that shovel out of your pack and see if you can find this unmistakable layer. Use caution skiing steep openings in the trees by skiing one at a time from a safe spot. Also remember that weak faceted snow likes to hang out by rocks and outcrops that one probably thinks are safe zones. Avoid ares where a wind slab or the snowpack gets thin- over convex rollovers, above cliffs and on the sides of gullies. Stability in upper layers of the snowpack is quick to assess. More difficult is the thin layer of faceted snow on top of the January rain/snow layer and the depth hoar/faceted layer near the ground. These layers have been stressed by recent snow and recent avalanches triggered by ski cuts show it could be stressed close to its breaking point well before your arrive for your ski descent. BOTTOM LINE The avalanche danger in the Mammoth and June Mountain areas is HIGH today on all wind loaded slopes steeper than 35 degrees. The avalanche danger rating is HIGH in steep glades and trees at middle elevations. Remember surface hoar likes open areas between trees and grows around rocky outcrops. The avalanche danger rating for all other areas in CONSIDERABLE on all steep wind loaded terrain. The avalanche danger rating is only a starting point. YOU CONTROL YOUR OWN RISK by choosing where and when you travel. Please note that the avalanche danger rating in this advisory expires in 24 hours. Backcountry travelers should be aware that elevation and geographic distinctions are approximate and that a transition zone exists between upper and lower elevations. Avalanches do not happen by accident and most human involvement is a matter of choice not chance. Most avalanche accidents are caused by slab avalanches that are triggered by the victim of member of the victim's party. Even small slides can be dangerous. Always practice route finding skills and carry avalanche rescue gear. Remember that avalanche danger ratings are only general guidelines. Distinctions between geographic areas, elevations, slope aspects and slope angles should be made.