Avalanche Awareness and off piste skiing tips from Henry's Avalanche Talk

Keep informed - Big high pressure, an early spring before winter returns

Since we last wrote there has been another 10-20cm.  the season rides on.   

 

Weather

There were big winds and a little snow on Tuesday. (See Andreas report below)  The bulletin points out that there may be some wind slab especially higher up

 

There is a huge high pressure (1040MB) dropping in now and it looks to be settled for all of next week.  Any snow or rain will be confined to the Eastern Alps and Austria.

 

So welcome to an early spring.  Lots of sunshine mild afternoon temperatures, Snow re freezing at night.  We could see spring like conditions next week.  Cold powdery snow where it is high and north facing.  Sun transformed snow on South ish facing slopes.

 

Next week offers the prospect of beautiful skiing, but you will have to hunt intelligently for good off piste - there will be plenty to be found.

 

If you believe long term weather models, they show winter returning from 4th or 6th February.  If they are right there will be lots of fresh snow for the half term school holidays

 

Safety

The snow pack seems to be stabilising (see Henry's comments below).  But look out for slides on the south side is the sun starts to have a big effect (wait and see)

 

Look out for wind slab on the North sie following the big winds on Tuesday as per the bulletin, but they say this is limited in scope.

 

As always you need to apply judgement at all times

 

Looking for the best snow

We gave this advice last week, but it seems even more relevant given the weather forecast for next week, so I left it in.    With the warmer weather that is forecast and a lot of sunshine next week.  It will be more important to look at slope aspect when you are judging where to find good snow.  At this time of year south east to south west slopes catch the sun and this will change the snow as the temperature goes up.  Slopes from north east to north west remain largely shady and it is here that you will find more powdery snow.  This is very apparent when you ski down gulley's and the character of snow changes as you ski from side to side.  Remember that is is not just slope angle but also slope aspect that affects how the snow responds to the sunshine.  Steep North facing slopes get no sun.   Low angle north facing slopes get oblique sun,  Low angle south facing slopes get some sun, but steep south facing slopes get intense solar radiation.  You can observe the effects of this by noticing the different types of snow you encounter as you ski around.

Still complicated but great fun

Today was the best day I have had for some time.  30cm fresh powder and glorious sunshine
See pictures in the La Plagne photo albums

La Plagne declared a risk factor of 3 today and it seemed like there were no slides triggered by skiers despite many people going on steep slopes immediately after the snowfall and against the advice of the Piste Patrol

The snow is stable in many places but we also saw a number of natural avalanches on slopes above 40 degrees on all aspects
On SE aspects we saw the snow continue to slide off the grass and cracks appear.

So watch out the situation remains complicated. 
More snow Monday night

Complicated situation evolving

Since we last wrote there has been at least another 30cm of new snow.  When the recent snow fell it was wet and heavy (see Roddy's reports)

 

Also we just heard on radio that English snowboarder got killed in avalanche in Tignes in the Tufs couloir. When we get some more info, we will post it on the blog.

 

It is now a complicated week for conditions and stability.  The risk level is 3 above 2000m.  This means that natural avalanches are unlikley but a single skier could trigger an avalanche when on any 30 degree or steeper slope oir when crossing at the base of a steeper slope.

 

There have been relatively few slides given how much snow fell, but be careful, as well as the Tufs incident today we know of another incident on the orientation table route on Bellevarde where a seasonnaire got taken over a small cliff and survived but was very shaken.

 

On the brighter side, the wet and heavy snow has all dried out above 2000m due to a dry clear night and there is plenty of nice snow to be had if you know where to stay safe.  If you are not sure play on lower angle slopes and keep an eye out for steeper slopes above you or convexities below you.

 

The Guides may be seen on the steeper slopes, since some of them are OK, but if you do not know how to tell which is OK and whihc is not then play safer when the bulletin shows a risk level fo 3.

 

The situatrion is likely to change rapidly but it is hard to predict.

 

If it stays warmish as forecast for the next 2 days, then the current snow will settle well and form a good layer for the next snowfall to bond with.  But this may not happen and our big advice is to track the conditions each day to see how the base layer evolves.  If you do that, then you will be in a stronger position to judge how unstable the situation will be when the next snow arrives on Friday night Saturday morning.

 

We are expecting some good colder snow on Saturday early morning provided the cold front from the west makes it through to displace the southerly weather system we have predicted for Thursday and Friday.

 

The longer term outlook shows more snow later next week on Monday and Wednesday.  There will be plenty of great skiing to be had.  Spotting where it is safe is a bigger challenge.

 

2 top tips

Track what happens to the current snow as the weather changes over the next 2 days

Stay on lower angle slopes if you are not sure about the risks until it is clearer that the risk levels have subsided.

 

Finding the best snow

Finding the best snow off piste when it has not snowed for 10 days and the snow has suffered wind damage can be quite a challenge and the best tip may well be just to get a professional guide.  Last week we discussed how you can look out for patches of good snow and by working out the slope aspect angle and altitude, you will be able to translate this into insights about where to find good snow.

 

The sunshine will affect slopes with different slope angle in different ways.  North facing steeper slopes will have very little sun in December January and will hold the powder for longest.  At present these slopes have powdery snow that is turning very grainy day by day or has been compacted by the wind.  This could create a weak layer underneath the next snow fall, we are watching to see what happens here.  Low angle North facing slopes tend to be wind affected and have a wind crust that is fine to ski on if you do not break through, but if you break through it can be challenging

On the south side it is different.  South facing steep slopes face the sun directly and deteriorate fast.  The sun's intensity is magnified per square centimetre due to the angle of the slope and facing the sun.   Lower angle south facing slopes have an angle to the sun and the sun works more slowly. (this is especially true in the morning before the sun has done its full damage.).  The bulletin highlights some risks on this slopes at the moment.  Interestingly some of the best powder and our video of people making powder turns was done on South east facing slopes

West facing slopes catch the warmer afternoon rays and can deteriorate badly.  See photo of recent slide in the Pays Dessert in Val d'Isere.

East facing slopes get the morning rays which will tend to be weaker and exist in lower temperatures.  So east facing slopes will hold soft powdery snow for longer.

If you not have a good grasp of which is North South East and East (or even if you do) a compass can be a great help to spot which slopes face where.  Given that nuances of slope aspect (10 degrees) can make a big difference, then the compass help even the most aware and experience people.

But within a single slope, there will be lots of different aspects which will produce different snow conditions across the breadth of the slope.  Here the nuances of slope angle become apparent.  So when you have decided to go down a slope, there can be big differences between one side and another or even in different parts of the track as you go down.  Have you ever followed a good guide and then deviated from his path and as a result found yourself in much poorer snow than the others experienced.  This can be true even if you are only 10m to the left or right of his track.  This is due to the nuances of slope aspect.

What you can do here is to practice looking at the slope and studying how the snow conditions change as you ski through it.  These observations will form the basis of your next judgement about where it is best to go.

Sunshine - slopes that face the sun may suffer snow melting even if they are above the freezing level. The sun can warm the surface of the snow.  So you need to take account of this when estimating where you might find good snow.  There is no magic formula for this.  You may often notice your guide banging the snow on the edge of the pistes with his sticks.  This will be to test the snow condition at any given altitude or aspect.  By reading the conditions you find as you ski, this will help you predict where the best snow will be.

Over the past 3 weeks we have covered a lot of ground about how to find the best snow.  The headline points have been.

• Get some good information - recent weather patterns, advice from experts, this is essential for you to know which of the factors have been at play over the past week
• Know how to understand the impact of the different factors

1. Wind
2. Temperature
3. Slope Angle
4. Slope aspect
5. Altitude

Look at what you find as you ski and update your understanding with real evidence gathered as you ski not just using predictions based on your analysis.

It may all sound very complicated, and clearly the experts have built up considerable experience that enables them to work out where the best snow is.  But in the meantime, you too can apply some of this thinking to improve your skiing experiences.  Even if you begin to think through some of these points you will get yourself into better snow conditions than if you do not

Read the actual conditions

Read the actual snow conditions and you can predict where the snow will be best

 

We have seen quite a few changes to the snowpack over the past week,  It has been one of those weeks where you cannot rely on the advice of your mates who tell you they found great snow yesterday in place xxx.  The wind and sun can change it all very rapidly and what was good yesterday may not be good tomorrow.  You have to read the conditions both before you go and when you get out there.

 

Any good off piste guide will know about the recent weather and recent snow reports and may well have advice from his team colleagues.  But you will always see them go and look at the actual conditions when they get out there.  When you see good snow (or bad snow) make a note of the altitude and aspect and shelter.  It is likely that in the same circumstances elsewhere, you will find similar quality of snow.  Today I found perfect powder in sheltered bowls facing south east at around 2500m in Tignes.  This was replicated later on Bellevarde.

 

The other evidence to look for is obvious signs of danger.  There are a number of small cornices with wind loaded slopes underneath.  This could be deduced by looking at the wind direction and the shape of the snow on the slope.  On 2 occasions we avoided crossing some 35 degree slopes with great powder just because we were not sure about the effect of wind loading.  A more experienced guide may have deemed it OK, but we were not sure so we played safe

Finding good snow in variable conditions

Having been out around Bellevarde and Tignes over the past 3 days, we have seen a marked change due to the effect of a southerly wind.  On Monday this wind reached 50km/hr above 2500m.

it is now 7 days since it last snowed and the temperatures remain very cold -10 to -15C so the snow is holding up well and remains in fantastic condition on the pistes, but if you are going off piste you need to look harder to find the best snow.  It probably requires expert guidance to work it out now. 

The recent snowfall fell in a NW wind or no wind.  This south wind is re arranging the snow.  Much of the obvious off piste is quite enjoyable but the condition is variable between, wind blown, wind crusted, slightly sun crusted on the south facing and some delightful patches of powder.

The Meteo France Bulletin tells us the snow pack is stabilising and the risk factor is now level 2 .  Keep an eye out for wind slab created by this southerly wind.  The bulletin tells us to be careful of the NW facing slopes.

We are expecting  glorious sunshine on Thursday and then some sun and cloud and milder weather this weekend.  Some forecasts say there will be snow, but this seems unlikely.

 

Some weather models point to a classic cold front coming in from the NW on Tuesday in time for Christmas.  But not all models say this, so we will have to wait and see

it is now 7 days since it last snowed and the temperatures remain very cold -10 to -15C so the snow is holding up well and remains in fantastic condition on the pistes, but if you are going off piste you need to look harder to find the best snow.  It probably requires expert guidance to work it out now. 

The recent snowfall fell in a NW wind or no wind.  This south wind is re arranging the snow.  Much of the obvious off piste is quite enjoyable but the condition is variable between, wind blown, wind crusted, slightly sun crusted on the south facing and some delightful patches of powder.

The Meteo France Bulletin tells us the snow pack is stabilising and the risk factor is now level 2 .  Keep an eye out for wind slab created by this southerly wind.  The bulletin tells us to be careful of the NW facing slopes.

We are expecting  glorious sunshine on Thursday and then some sun and cloud and milder weather this weekend.  Some forecasts say there will be snow, but this seems unlikely.

 

Some weather models point to a classic cold front coming in from the NW on Tuesday in time for Christmas.  But not all models say this, so we will have to wait and see

What a week! now for the sunshine.

With off piste skiing, it seems we are either waiting for more snow or fretting about the avalanche risk.  At the moment I would worry about the avalanche risk.  Val is reporting level 4 risk after a week in which between 1m and 1.5m of snow fell and fell rapidly not slowly.

Dom and his friends sucking up the powder in the Grand Montets near Chamonix today
see Cham photo album

 

The most stable conditions are created when the snow falls steadily in small amounts 10-20cm at a time and builds up slowly.  What we have now is 1m of fresh snow on top of a weak layer (especially above 2200m).  Above 2200m there has been no warming or rain.  Below that level the temperatures have been more volatile. which will stabilise things a bit more.  However from reading the bulletin great caution is needed every where.

 

Risk level 4 means it is possible to trigger a slab avalanche on a steep slope when you are on a less steep slope below it.  So with this risk factor, you not only need to avoid slopes greater than 30 degree angle, but you also need to ensure you do not ski too closely underneath a steep slope.  Or if you do, ski quickly lightly and one at a time, ensuring you gather together in islands of safety.

 

The outlook is for stable cold and sunny weather as far ahead as the forecasters can reasonably predict.  So a great sunny cold weekend awaits.

 

 

Future ezines will be on Thursdays - next one on 19th December

Staying safe in avalanche risk level 4

In these conditions one of the best ways to stay safe and have more fun is to think not just about where to go but about "how you go".  Don't get smitten by "powder frenzy".  there are a number of points around this and the exact decision must be based on a judgement about where you are, the size of the group, the skill of the group, the fitness of the group and the general mood and attitude.  But these three points always matter and remain important.

• Ski one at the time, - this reduces the pressure on the slab and dramatically decreases the chances you will trigger the slab to slide 
• Cluster together and wait for your friends only in islands of safety
  
• Don't ski above other skiers,.  To trigger an avalanche on to someone else is a few steps worse than bad manners, you might end up in court for manslaughter.

Often this is the difference between an avalanche and an accident.  These factors are even more important in risk level 4 - which is where we are right now

Weather forecast Val d'Isere

Issued Wednesday, December 12, 2007, 19:30
Status and trends
The anticyclone sticks
Sustained dry and cold (at least until Tuesday night).
The snow and cold is tempting but dangerous over 1700m.
There will be ample time to enjoy later.

Tomorrow, Thursday, Dec. 13:
You can still see low clouds linger, but perhaps less
Today. The sky was clear in the mountains, day and night, and a little windy
in the east.
Pressure 1032 mb
In plain: -5 / +6 ° C, low wind East
At 1500m off-: -4-> -1 ° C, wind ENE / 8 knots then low
At 3000m off-: -8 ° C, wind Est/14-> 9-> NE/15 knots
Iso 0 °: 100/1400m
Iso -10: 3300-> 3900m
Iso -20: 4800-> 5300m

Friday, December 14:
The northeast wind becomes strong enough in altitude.
Some clouds are possible without consequence in the afternoon.
Pressure 1034-> 1030 mb
In plain: -5 / +6 ° C, low wind NE
At 1500m off-: -1-> -4 ° C, wind NE/9-> 13-> East / 8 knots
At 3000m off-: -5-> -9 ° C, wind NE/15-> 28-> (night) 23 knots
Iso 0 °: 100/1500m
Iso -10: 4000-> 3200m
Iso -20: 5300 -> 4900m

Saturday, December 15:
Perhaps partly cloudy on the Southern Alps, but not here.
The cold increases, the wind decreases, the valleys of the south can lug of
The afternoon clouds.
Pressure 1029 mb
In plain: -7 / +4 ° C, low wind
At 1500m off-: -4-> -8 ° C, wind Is> SE / 7 knots
At 3000m off-: -9-> -15 ° C, wind NE/20-> SE / 9 knots
Iso 0 °: 0/900m
Iso -10: 3100-> 2000m
Iso -20: 4900-> 3900m

Sunday and Monday
Beautiful and cold in a moderate easterly flow.

Weather Forecast Savoie Haute Savoie

Issued Sunday, December 9, 2007, 19:16

Tomorrow, Monday, December 10:
It rains frequently with snow above 1200 and 800m, fairly abundant
Around 2400 in a strong westerly wind and Northwest more moderate.
The contribution of snow expected exceeds hardly 25cm for the day, contributing
Yet the accumulation of slabs.
Pressure 1001 -> 1014 mb
In plain: 5 ° C, wind SW/10-> West / 6 knots
At 1500m off-0-> -3 ° C, wind Ouest/20-> NW/14 knots
At 3000m off-: -10-> -12 ° C, wind Ouest/35-> NW/24 knots
Iso 0 °: 1300-> 900m
Iso -10: 2900-> 2500
Iso -20: 4100m

Tuesday, December 11:
The cold increases, 
There is still a little more snow in the morning from 500m
(+10 / 15 cm on average mountain)
Pressure 1014 -> 1025 mb
In plain: 3 ° C, wind WNW/6-> NNW/10 knots
At 1500m off-: -3-> -6 ° C, wind Nord/14-> 18-> 14 knots
At 3000m off-: -13 ° C, wind Nord/25-28 knots
Iso 0 °: 1000-> 600m
Iso -10: 2400m
Iso -20: 4000m

Wednesday, December 12:
The air is much drier, the sky was clear from the night to 1600m and

Pressure 1026-> 1032 mb
In plain: 0 / 3 ° C, wind north / 7 knots decreasing
At 1500m off-: -6 ° C, wind NNE/14-> ENE / 9 knots
At 3000m off-: -13-> -9 ° C, wind NE/24-> 10 knots
Iso 0 °: 500-> 900-> 0m
Iso -10: 2500-> 3200m

Thursday
Good weather calm, cold still significant risks.