Another nice day yesterday until the next weather system decided to move in.

Back to winter conditions in the Alpine this week with a few breaks, warmer tomorrow but cooler as the week progresses. This week will not be a repeat of last week. 


I know I have been talking about spring conditions but the snow pack has not yet gone isothermal in the alpine. 


Spring Hazards
Full spring conditions typically consist of an isothermal snowpack - One which is at 0 Deg C throughout. The surface will refreeze overnight, and as it softens in the sun good "corn" snow makes great skiing. The hazard tends to follow a daily cycle of low in the morning and moderate in the afternoon. After softening too much wet slides can release, often starting as point releases and growing. A good rule of thumb is to head home when you start to sink to your boot tops.
Another hazard to keep in mind is that before softening up the snow can be icy and a fall can be dangerous.
Large wet slides can be a hazard in the early spring, typically for a period of a few days when the snowpack first becomes isothermal. One reason for this is that free water can be introduced to snowpack too quickly if rapid warming occurs, especially if refreezing overnight does not occur. Initially this free water can flow along and lubricate buried bed surfaces, leading to wet slab releases. The effect of free water in the snowpack can be very difficult to predict. Ultimately, the free water and the melt-freeze process will hinder fracture propagation and break down the layering in the snowpack. After isothermal conditions prevail for a while the hazard of wet slabs becomes small.

At 2280 meters as of 06:00 the temperature was -5, winds were 15-30 KPH from the SSE.
At 1550 meters the temperature was -2, 98% relative humidity and the barometer is falling.
1 cm of snow fell there last night by 06:00.
It is +3 in the valley.

The snow will continue through the day and winds should pick up in the alpine.

For the updated Avalanche Advisory click here: Avalanche Advisory

Update on Avalanche in Kashmir Area: Siachen Glacier

North Face helping educate: Know Boundaries

Snow Bridge collapse: Valle Blanche

Avalanche Awareness and Mountain Snowmobiling survey: Great Prize for completing

The ice is almost gone off Alta Lake. The warm valley temperatures in the past few days melted a lot of snow and ice.

April 15 Th 2012,  north facing slope at 2260 meters below cornice at 09:30 hrs. Depending on how the new snow arrives there will be isolated pillows of snow that will likely be easily triggered on this surface hoar.

The spring skiing has been very good, moving around to different elevations and aspects is key!!

As of 06:00 the temperature at 2280 meters was -6, winds were 10-15 KPH from the S.
At 1550 meters the temperature was -2.5, 77% relative humidity and the barometer is rising.
In the valley it is -1.

For the latest Avalanche Advisory click here: Avalanche Advisory


In the past 2 years in the States skiers are becoming the #1 statistic: US Avalanche Statistics

What does fresh tracks skiing cost: Interesting Comparison

Older footage but cool narration: In your backyard

Poor footage but an amazing slab release: Large Slab

From E Chapelle's work in 1960: Heat and vapour transfer in snow.

The flow of heat through snow is a complex process. Snow, particularly at low densities, is a good thermal insulator. Like other insulating materials, it transfers heat by a combination of molecular conduction through the solid framework, by conduction, diffusion and convection of the entrapped air, and by internal radiation exchange. Unlike other insulators, it also transfers heat by sublimation of the solids--in this case ice--and associated diffusion and convection of the vapor phase. The latent heat of sublimation of ice is high, 680 calories per gram at the freezing point; consequently water vapor can be an efficient means of heat transport within snow which introduces complicating factors in the bulk thermal conductivity. Owing to this contribution of water vapor to heat flow, the bulk, conductivity becomes dependent on absolute temperature as will be demonstrated below, Moreover, recrystallization of ice which has passed through the vapor stage rearranges the solid framework and effects a permanent time- dependent change of conductivity, In addition-to thermal effects, this latter change also profoundly alters the mechanical properties of snow: the stabilizing and strengthening effects of destructive crystal metamorphism are reversed and the snow becomes mechanically weaker.

Temperatures have kept the snow firm in the morning. When it does soften up and your timing is good the spring skiing is excellent. Good corn to be had in the back country as well.

There is a big increase in the amount of snowmobiles in the back country.

At 2280 meters the temperature is - 6 as of 06:00. Winds were 5-15 KPH from the SSE.
At 1550 meters the temperature is -2, 88% relative humidity and the barometer is on the rise.
In the valley it is -1.

For the updated avalanche advisory click here: Avalanche Advisory

A definition of high marking: Useful Tips

Another perspective on snowmobiling: Many Opinions

Snowmoiling safety tips: Good Information

When things go wrong: Avalanches are not the only hazard

Cool trick: How do you ride



Wet snow avalanche definition

A wet slab avalanche is the slowest moving type of avalance, but can still be extremely dangerous and leave unbelievable destruction behind.

Air and ground temperature, the steepness of the landscape, the type of snow or precipitation falling, and how the snow or precipitation settles on the ground are all factors that determine what type of avalanche can occur.

Wet slab avalanches often happen in the springtime when the air temperature starts to rise and more rain than snow falls changing the overall composition of the snow.

The biggest contributor to the creation of a wet slab avalanche is water. Skiers should be aware as spring approaches and the days begin to get warmer, a perfect scenario for a wet slab avalanche could be in the making. Although slow moving, this type of natural disaster can be very damaging.

The wet, heavy, often rain soaked snow has the power to move boulders, trees, mud, and anything else it its path. When the moving mass finally reaches its destination, it often looks as though it has transformed into a wall of dirt and debris.

Some of the jumps being built are huge.

Mt Fee

Another great day yesterday, lots of convective activity.

A convection cloud is a cloud that forms from the air rising in that place. When the sun heats the earth, the air right above it gets warmer and rises. Because of the lesser pressure above, it cools down by adiabatic effect and when it moisture contentreaches what is called dew point temperature, it condenses as a cloud.

Usually those are cumulus clouds and their base is exactly where the air is a dew point temperature.

But once it starts condensing, the moisture give away energy in form of heat. That keeps the cloud rising. When it finally reaches a place where the temperature equals that of the surrounding air, it stops rising. That's the cauliflower top of a cumulus cloud. Each top is an air parcel that rose in a "bubble" of warm air.

If the air aloft is very cold, the "bubbles" will keep rising all the way to the top of the troposphere. The cloud is then called a cumulonimbus and it may become a thunderstorms.

At 2280 meters the temperature was -6, winds were 5-15 KPH from the E as of 06:00 Hrs.
At 1550 meters the Temperature was -2.5, 100% relative humidity and the barometer was rising.
In there Valley it is +3.

For the updated Avalanche Advisory click here: Avalanche Advisory

An interesting American site: Open Snow

Setting off a large avalanche in Japan: Touchy Conditions

Propagation Saw Test on a grand scale in Utah 140 cm wide and 11 meters long: Interesting Results

Definition of an isothermal snow pack: Isothermal

# 13 had to have something in here with a 13!

Thursday April 12 Th was the Mom's Classic

Near Refuse Pinnacle on the Spearhead Traverse, wind effect from Sunday. Dave Sarkany Photo

As of 06:00 at 2280 meters the temperature was -4, winds were 5-15 KPH from the S.
At 1550 meters the temperature was -1.5, and the relative humidity was 100 %, with the barometer on a consistent slow rise. In the valley it was +4. At the Catskinner weather plot 3 cm of new snow was recorded over night.

In the past few days loose snow avalanches have been reported , some releasing up to size 3 slabs.


For the latest Avalanche Advisory click here: Avalanche Advisory

Footage from TGR of avalanches from the 2012 season: Amazing more people are not buried

Its a bit long but a good perspective on being buried for a while: Air pocket is important

So far April has brought below normal precipitation and warmer than average temperatures.  La Nina is going away and we may have a nice summer compared to last year.

According to some meteorologists the US  is falling behind in their forecasting abilities due to a lack of computer power. The European Centre for Medium Range Weather Forecasting (ECMWF) and the Canadian Meteorological Centre (CMC) both have better computers. Some of our local weather forecasts are compiled in the US.

Here is the link to the ECMWF: European Models

Here is the link to the CMC: Canadian Models

Where we were to what we have now, 6 days and its not the same!!

    April 4, 2012

    April 10, 2012

East facing on Cloudburst, Avalanches from last week.

At 2280 meters as of 06:00 hrs the temperature was -1, winds were 10-20 KPH from the ESE. At 1550 meters the temperature was +1, 82 % relative humidity and the barometer is on a slight decline. In the valley it is +2.

The forecast keeps calling for rain and even though it appears that way during the day we have been dry.

For the update Avalanche Advisory click here: Avalanche Advisory

The mountains have many hazards, going for a nasty slide: Grab the rope

Some different locations with skiing and avalanches: Good Footage

More snowmobile avalanche footage: Buried

Quick clip of skier initiating a slab: 30 Seconds 

The warming temperatures are releasing pillows of snow on steep, unsupported terrain, and tree bombs have also been falling. Report of a wet size 2 slide onto singing pass trail yesterday. 

Even the winds from Sunday help to get cornices looking like this.                  R. Bougie Photo

At 2280 meters the temperature was 0, winds are 10-25 KPH from the ESE as of 06:00. At 1550 meters the temperature was +2, 70 % relative humidity, and the barometer is dropping slightly. No new snow, and in the valley it was 0.

For the Latest Avalanche Advisory click here: Avalanche Advisory

Speed kiting and ski cutting,  who would have thunk: Avalanche Control on the Fly

Urban Avalanche in Scotland: Roof Avalanche

Jeeps and Avalanches: Jeep Commercial

After the wild winds on Sunday thought I should bring up the topic of Anabatic and Katabatic Winds:

An anabatic wind, from the Greek anabatos, verbal of anabainein meaning moving upward, is a wind which blows up a steep slope or mountain side, driven by heating of the slope through insolation.^[1][2] It is also known as an upslope flow. These winds typically occur during the daytime in calm sunny weather. A hill or mountain top will be radiatively warmed by the Sun which in turn heats the air just above it. Air at a similar altitude over an adjacentvalley or plain does not get warmed so much because of the greater distance to the ground below it. The effect may be enhanced if the lower lying ground is shaded by the mountain and so receives less heat.

The air over the hill top is now warmer than the air at a similar altitude around it and will rise through convection. This creates a lower pressure region into which the air at the bottom of the slope flows, causing the wind. It is common for the air rising from the tops of large mountains to reach a height where it cools adiabatically to below its dew point and forms cumulus clouds. These can then produce rain or even thunderstorms.^[2]

A katabatic wind, from the Greek word katabatikos meaning "going downhill", is the technical name for a drainage wind, a wind that carries high density air from a higher elevation down a slope under the force of gravity. Such winds are sometimes also called fall winds. Katabatic winds can rush down elevated slopes at hurricane speeds, but most are not that intense and many are on the order of 10 knots (18 km/h) or less.

Not all downslope winds are katabatic. For instance, winds such as the Foehn, Chinook or Bergwind, are rain shadow winds where air driven upslope on the windward side of a mountain range drops its moisture and descends leeward drier and warmer. Examples of true katabatic winds include the Bora (or Bura) in the Adriatic, the Bohemian Wind orBöhmwind in the Ore Mountains, the Mistral, the Santa Ana in southern California, the Tramontana and the Oroshi in Japan.

Yesterday I had mentioned the slide on Overlord, here is some information and pictures from Andre Charland. 

Date

2012-04-08

Location

11:50am

Location Description

Bottom of Overlord Glacier

Province

BC

Mountain Range

Coast Mountains

Coordinates

Elevation

1900m

Activity

Backcountry Skiing

Involvement

-

Injury

-

Fatality

-

Description

Skier traversed from flatter ridge heading skiers left into the middle of a moderate pitch convex slope that was wind loaded. A stiff slabbed release and the skier was able to ski out of it to the skiers right. It appeared to have released above the skier and step down a layer. Debris was large blocks up to 2m and very dense.

Date/time	Size	Type	Trigger	Elevation	Aspect	Slab width	Slab thickness
2012-04-08 22:16	2	S	S	1900	w	75m	50cm

Present Temp	Max Temp	Min Temp	24hr Trend	Wind Speed	Wind Direction	Sky Condition	Precipitation Type & Intensity
-5	-	-	Rising	M	E	CLR	None

Weather comment

Very strong winds the night before from the east.

Snowpack	24hr Snow	Storm Snow	Storm Date
-	0	70	-

Snowpack comment

Wind pack, however was blower the day before in none sun affected aspects.

Looking around the corridor there have been some large results from a few days ago.

At 2280 meters the temperature as of 06:00 hrs was -2. Winds were out of the SSE at 10-20 KPH.
At 1550 meters the temperature was 0, 62 % relative humidity and the barometer is falling slightly.
In the valley it is +1.

Report of a size 2 Sa in a gully feature on  Overlord Glacier around 12:00 yesterday. Three ski tourers doing the Spearhead. No involvement, not wide but stepped down so it was deep. Winds were certainly having their way with the snow yesterday. In places mother natures grooming was certainly evident with the wind transported snow.

For the latest Avalanche Advisory click here: Avalanche Advisory

Sledder near Alpine Wyoming gets lucky: Wet Slide

Dirt Bikes & Avalanches, What next? : Dirt Bike in an Avalanche

Snowmobile doing cornice control: Close Call

Falling off a cornice: Walking on a cornice?

And yet another person falling off a cornice and into an avalanche: Going Down

Update on Avalanche in Kashmir: 139 Now presumed buried

The cornices in our area are huge, its wise to stay away from them!!

Wet snow avalanche.

Overview of slide North of Mt Fee from yesterdays post. Avalanche occurred April 6, 2012.

At 2280 meters the temperature is - 7, winds were 25-45 KPH from the E as of 06:00. At 1550 meters the temperature is -5, 73 % relative humidity and the barometer is declining slightly. In the valley it is -1.

Surface Hoar from April 7, 2012, developing in protected areas.

For the updated Avalanche Advisory click here: Avalanche Advisory

What it would be like being hit by a small avalanche from behind: Dry And Fast

Nothing like being dug out quickly: Short Clip

135 Missing after avalanche in the Pakistan\India Border: There is a lot of snow

Another report with some history of the area: Siachen Glacier

Some information on the ACMG blog: Spearhead

More avalanche news from Europe: Austria


Some photos from Braden Douglas from Decker Yesterday:

Huge Cornice

Natural on Decker- ran shortly after storm sz 2.5

-Decker shoulder- ran during storm all the way down to decker meadows sz 3

-SW side unsupported rocks- recent

Very Large Cornice

Storm slide off Decker form last week

Old Fracture Line

Recent Slab Avalanche in the Rocks


Some news from the Duffy :
NW, NE, N slopes skiing well to about 1600m.  Corn on true S slopes starting around 2-3pm or so.



Some natural releases on E slopes - probably solar : From Lee Lau

If you have not had the time to do it yet, please fill in the Spearhead Hutt Survey, click on this to get to it: Spearhead Huts

Not the best place to ski cut or board, certainly hard to High Mark?? April 6, 2012

At 2280 meters the temperature was -10, winds were 5-15 KPH from the E, as of 06:00.
At 1550 meters the temperature was - 8, 89 % relative humidity and the barometer is steady.
In the valley it is -4. No new snow over night.

Some Na size 1-2 avalanches on solar aspects, some isolated Sa on very steep terrain like this example.
Not much activity considering the temperature.

For the latest Avalanche Advisory click here: Avalanche Advisory

Snow boarder pops his Snowpulse: Going Down

Snowmobiling in Norway, not fast enough: Fast moving slide

Took a lot of effort to get there!!

Size 2.5 just north of Mt. Fee snowmobile access skiing or snowboarding release. Wow no one dead!! April 6 2012. Slide ran over there snowmobile tracks. NW aspect.

Epic just getting to where the trigger point is!!

Access point, lots of sleds involved in this adventure.

How strong is the sun this time of year. Picture below was taken in the valley at 08:00 East facing slope, air temperature -5.

New snow, solar aspects, strong sun = Avalanches


At 2280 meters the temperature was - 11 as of 06:00. The winds were 0-5 KPH from the SSW. At 1550 meters the temperature was -8, 92 % relative humidity and the the barometer is rising. In the valley it was
 - 5. No new snow over night.

Good settlement and tightening in the snow, but the cornices are still large, crust on all solar aspects, and surface hoar is developing on sheltered north facing slopes.

For the updated Avalanche Advisory click here: Avalanche Advisory

What it would be like getting caught in a wet slide: Sierra Spring POW

Interesting study out of Switzerland on burial statistics: Time is a factor

Ski Touring in Alaska, big country, big rides: Talkeetnas

If you go out on the Spearhead be diligent and fill in this survey: Hut Survey

Some more information on tree wells:

Treewell Safety
NARSID stands for Non-Avalanche Related Snow Immersion Death. NARSID incidents occur with deep snow or tree well immersions, in which a rider or skier falls into an area of deep, unconsolidated snow and becomes immobilized. The more the person struggles, the more entrapped in the snow they become, and risk suffocation.
     • Each skier or snowboarder controls his or her own level of risk and are the only ones that can prevent this type of accident from happening. Always ski and ride with a partner. To minimize your risk, you must know how to travel safely with your partners in these un-groomed deep snow areas
     • Always stay in visual contact so that your partner(s) can see you if you fall. Visual contact means stopping and watching your partner descend at all times, then proceeding downhill while he or she watches you at all times. It does no good if your partner is already waiting for you in lift line while you are still descending the slope;
    • Stay close enough to either pull or dig out. If you have any question about what "close enough" to assist someone in a tree well is, hold your breath while you are reading this. The amount of time before you need air may be how much time your partner has to pull or dig you out of danger. Other factors such as creating an air pocket or the position you fall in, may affect this critical timeframe.
    • Remember, if you lose visual contact with your partner you could lose your friend. It is important to know that most people who have died in deep snow or tree well accidents had been skiing or riding with "partners" at the time of their accident. Unfortunately, none of these partners were in visual contact so they were not able to be of help in a timely manner.


A dedicated site to tree well & deep snow issues: Tree Well & Deep Snow Safety

Posted this video already this year, but here it is again: Tree Well Rescue

Fresh off the Press

Grizzly lake today! Sledder got stuck on hill, buddy drives over top of him and cuts the slide. Stuck guy was taken about 60m Thanks to Peter Norie for the information. April 5, 2012

Same location as fatality last month.

I watched it happen from the other side of the valley. Victim drives right up the slope and gets stuck. You can see his track on the left into the slide area. His riding partner goes up the back side and descends down the hill towards him. The slide let go before the upper sledder reached the future fracture line. We watched it all go down in complete amazement that more people don't die in the backcountry doing what these two did!

One of several size 2.5 avalanches from explosive control on Blackcomb yesterday. The slide path referred to as Rock Shot 1 ran into the Hour Glass releasing it, then running out to the lake in Ziggy's Meadow.

At 2280 meters as of 06:00 the temperature was -10, winds were 10-20 KPH from the NNE. At 1550 meters the temperature was -7.5, 95 % relative humidity, and the barometer os on the rise. No new snow over night. In the valley it is -2.

Field observations from yesterday in the corridor, natural avalanches from size 1-3 during the storm, natural activity in the am up to size 2.5 and natural size 2 on solar aspects in the pm.

Did anyone get pictures of the slides in the Spearhead yesterday??

For the updated Avalanche Advisory click here: Avalanche Advisory

Sad to report a tree well tragedy: Snow Boarder found in tree well

Large avalanches near Elkford B.C. : Smith Basin

Another result from explosive control on a path referred to as Tifosi.

Unsettled weather for a few days, hopefully the new snow gets a chance to settle out.

At 2280 meters the temperature was - 12 as of 06:00. Winds were 0-10 KPH from the SE. At 1550 meters the temperature was -9, 95 % relative humidity, and the barometer is on the rise. At that elevation 7 cm of new was recorded, and 8 cm at pig alley. In the valley it is -2.

Natural avalanches (Na), Skier Accidental (Sa), Explosives (Xe), Ski Cutting (Sc) from size 1-3 recorded in the corridor yesterday. Some activity was stepping down into the March 27 th interface.

Yesterday 22 cm was recorded at pig alley during the day, for a 24 hr total of 62 cm. Not bad for an April Storm. A size 3 slide was initiated with explosives on the hanging roll yesterday.

It is unfortunate that people are still disobeying avalanche closures and skinning into areas where potential avalanche control could be initiated. Just because the alpine is closed does not mean that at some point of time in the day the Ski Patrol will not try to test or control slopes when they are able. Control work is essential to protect machinery which is used at night to keep the mountain opened for our skiing pleasure.
Use your brain and go touring some where else.


For the latest Avalanche Advisory click here: Avalanche Advisory

Creating an avalanche, jumping off a cliff then filming it from the air: Air Borne Avalanche

Knocked down by a size 1: Pole Cam

Spearhead Hut Survey, click here: Hut Survey

Just a little wind effect.

Traverse into Disease Ridge popped out slide Sunday.

You can see the first traverse into the chute where we backed off and
decided to go in higher and ski cut. The fracture line sort of lines up with
the lower traverse line, so it appears that that was where the fracture
occurred, but it wasn't. It was a good a wakeup call for us to see the snow
slide well beyond the flats and continue to travel uphill onto the moraine
at the bottom. 

At 2280 meters as of 06:00 hrs the temperature is -5, winds are 75-100 KPH from the SSE.  At 1550 meters the temperature is - 2, 99 % relative humidity, and the barometer is dropping.  At that elevation 23 cm of snow fell over night. At Pig Alley 40 cm was recorded. In the valley it is
 +1. 


 Size 1-1.5 SSL were reported yesterday where people could get to.  


Yesterday afternoon a gust of 125 KPH was recorded at the Horstman Hut at 15:30. Over night the Max gust was recorded at 117 KPH at 02:30.


For the updated avalanche advisory click here: Avalanche Advisory

Another avalanche fatality in Colorado: March 30

Snowboarder gets caught in large avalanche: Engulfed

When and where will there be flooding: Snowpack Science

Scary ride in Canmore: Avalanche