Avalanche Advisory Archive Pre-2016
| Date Issued: | 2014-03-24 |
|---|---|
| Danger: | 2 |
| Trend: | 5 |
| Probability: | 0 |
| Size: | 3 |
| Problem: | 0 |
| Discussion: | ... HIGH WIND WARNING FROM 4 PM THIS AFTERNOON TO 4 PM AKDT TODAY ... MOSTLY CLEAR ... LOCALLY VERY WINDY. HIGHS AROUND 40. TONIGHT ... PARTLY CLOUDY ... LOCALLY VERY WINDY. LOWS 23 TO 29. NORTHEAST WIND 15 TO 25 MPH ... EXCEPT NORTHEAST WIND 20 TO 30 MPH WITH GUSTS TO AROUND 80 MPH NEAR DOWNTOWN JUNEAU AND DOUGLAS. TUESDAY ... PARTLY CLOUDY IN THE MORNING THEN BECOMING SUNNY. The high wind that was supposed to come last night and today has been pushed off till late today into tomorrow. This wind event when we get it will be a great natural trigger, kind of like hitting a slope with explosives would be. From the weather service foreast discussion: The alpine NW - SW - SE aspects have been seeing enough solar action to create a slight surface sun crust which is helping to hold things in place when it has been cooled enough to refreeze, but hazard is also going up each afternoon as this re-melts and the snow cooks in the sun. Winds have remained out of the NE at the tram, and both the Tram and Mt Juneau have had steadily falling temps since sunset last night. Mt Juneau is currently -8.5c (17f). Danger will increase as the winds continue and particularly as we hit the high winds this afternoon into tomorrow. For now I expect sizes to remain medium (class 3 or less), but that will change with enough new wind loading. Main avalanche problem today is wind slabs. A good size wind slab may pop out pockets on the buried facet layer near the Jan Crust, but those will be isolated and not continuous enough to constitute a large problem in the urban paths. This is not a good afternoon to beach comb beneath Snowslide Creek on Thane Rd. or be spending much time on the Flume/Perseverance trails. Hazard is not that high this morning but will be increasing in the afternoon significantly. Also note that while this forecast is a tool that we compile by looking at snow data from all over our local mountain ranges it is targeted at the slide paths that impact CBJ homes, roads, and trails, not general backcountry travel. There is a lot of spatial variability out there right now, and our start zones are not representative of many recreation zones. Avalanche Danger for the urban zones is MODERATE this morning - rising to CONSIDERABLE tonight as winds increase: Natural avalanches possible; human-triggered avalanches likely. Small avalanches in many areas; or large avalanches in specific areas; or very large avalanches in isolated areas. Be increasingly cautious in or under steeper terrain and in avalanche zones. Monitor avalanche forecasts. |
| Tip: | MANAGING AVALANCHE TERRAIN (3) I have tried to help outline the avalanche problems this year. Just another way to describe the dymanic is that is creating the current hazard. Now let?s start to talk about ways to deal with managing hazard during winter travel. There is an old adage among backcountry ski guides that when avalanche danger is the problem, terrain choice is the solution. TERRAIN SELECTION This is what it is all about. People need to base their terrain choices on the hazard that exists in the zone they are headed to. There a number of resources in town to help identify the current avalanche problem, depending on where you want to go. This forecast is one of them though certainly not representative of what you?ll find up Davies Creek. It is important to realize that, within a rating level, likelihood or consequences are often weighed differently. For example: a danger level of moderate could mean a situation where the likelihood of triggering an avalanche is low but its consequence is high/fatal (such a situation is also referred to as \"dangerous moderate\", which is often the case in connection with Persistent Slabs). In this forecast Urban concerns, usually based off the overall size of slides, helps guide the danger rating. Understand that a size 3 or 4 slide that is necessary to hit houses and roads is not what kills most backcountry users. Those are smaller slides, on smaller slopes. Therefore, before heading into the backcountry, sidecountry, slackcountry, upcountry, badasscountry and whatnotcountry, always do a thorough tour plan thinking through the process of how the current specific avalanche problems are distributed, on what kind of terrain they live. Once you know the \"dragons den\", you then make your terrain selection, still at home, looking over maps, area photos, google earth, guide books, etc. NO-GO ZONES This terrain selection should consist of a precise description of no-go zones (areas you and your group members agree not to travel on that day no matter what), marked on your topo map, leaving wiggle room, options, for less aggressive and safer terrain. To ski the \"less aggressive\" terrain, you need to find a collection of clues that would encourage you to travel there - finding no clues or clues pointing towards the avalanche problems would move that terrain to the no-go zone. Therefore, it is important to have terrain options up your sleeve that are considered hands-down safe for the day's conditions; having such alternatives will make it much more likely you'll actually go there if needed instead of skiing dubious terrain \"one at a time\". Once touring, having set a firm boundary on what terrain to avoid (the no-go zones), it is ok to modify plans on the fly since there are many good options to choose from. Every avalanche professional will have near miss stories, by far the dumbest one of mine involves violating our \"no-go\" zone near Mt Troy that we had agreed on earlier that day, then kicking off a slide that almost took me for a 1000ft ride. For other insightful cases check out: http://avalanche.state.co.us/caic/acc/acc_report.php?accfm=inv&acc_id=526 http://avalanche.state.co.us/caic/acc/acc_report.php?accfm=inv&acc_id=518 http://avalanche.state.co.us/caic/acc/acc_report.php?accfm=inv&acc_id=505 |
| Forecaster: | Chris Eckel |