3 day Ski Touring in Hurrungane

It's a while since I last studied glacier rescue now. Feeling a bit rusty when we practised on course, I figured freshening up a bit with a short blogpost in the subject would not hurt.

Picture 1,  Two Team Haul

Crevasse Rescue Systems
There is several systems that can be used for different situations.

Two Team Haul
If two teams are available, a two team haul can be used. If the second team can get a rope relatively quick to the victim it would not be necessary for the first team to build an anchor. Meanwhile the second team approaches the edge and drops down a rope with a locking biner, the first team belays the victim in self arrest position. Remember to secure the edge with a backpack, ice axe or something else before lowering the rescue rope.

Picture 2, Droop Loop Raise

Drop Loop Raise
Low friction system that moves the rope quickly.
It has minimal mechanical advantage so it suits a light victim or two or more rescuers available to haul.

Picture 3, Z Pulley

Droop Loop with Z Pulley
This method is the most common when there is only one rescuer. It has greater mechanical advantage, but the increased friction and rope stretch reduces efficiency.

Picture 4, Z Pulley with added advantage

Z Pulley with Added Advantage
The difference from drop loop to z pulley as you can see on picture 2 and 3, is the ratchet and another prussic. To add advantage to the system use another prussic as shown in picture 4. This system has such an high friction, rope stretch and slow raise, so its only used when previous systems can not create enough advantage to haul.








References:

Pavillard, J. et.al (1999). Techncal Handbook for Professional Mountain Guides. ACMG, Canmore, AB.

Haslene, S. (2008). Breboka - Håndbok i brevandring. DNT Fjellsport, Oslo.

Guide's trip

On the way up to Austerdal glacier. Photo: Mathilde Andersson

The past few days from the 12th to the 14th Eirik and Sara third years, Mathilde and I second years and five first year students drove up to Veitastrond for a short glacier trip. We were walking on Austerdal glacier with the view of the beautiful Odin, Thor and Loke glacier when I figured out I wanted to write a post about snow.


Formation and Growth of Snow Crystals in the Atmosphere
The atmospheric clouds compounded of supersaturated water vapor droplets, are the mother of all snow crystals. Droplets are formed by water building up on small particles of salt, dust or soil in the air called condensation nuclei. The droplet will grow when the air is supersaturated and water vapor condensate on the surface. Snow can be formed by tiny ice crystals when the air temperature is below zero degrees however, small water droplets will persist in a supercooled state. Freezing ice crystals are only formed when foreign particles are being crystallized. The freezing nuclei are less common compared to the condensation nuclei. Their special structure promote freezing individually by the temperature gradient and they increase in numbers when the temperature decreases. Droplets will freeze without assistant from the freezing nuclei at minus 40 degrees (Clung & Schaerer, 2006;43).

Crystallographic axes of a snow crystal
(Wergin & Rango, 2002).

The ice crystals will fall when they gain enough weight. On the way down they will become larger by colliding with other supercooled droplets that would freeze onto them, this process is called riming. When the branches on the crystal are entirely filled in by an extended riming process, it becomes a rounded crystal called graupel. Hail is formed by graupel alternating in a freeze and thaw cycle (Clung & Schaerer, 2006;45).

Basically the growth of a snow crystal occurs in two directions, the a-axis that form plate like crystals and the c-axis that form needle like crystals. On vapor growing crystals there will always be six sides due to the basal plane of the crystal. The temperature is the most important of all the complicated variables that form the crystals both on the way down and on the earth after the snowfall. The growth direction switches from a-axes to c-axes when the temperature changes. The crystals that have fallen through cold air are generally smaller than those falling through warm air due to its ability to hold more moister (Clung & Schaerer, 2006;46).


The Perfect Flake
Snowflakes form in warm and moist air with calm to light wind speed. When the cloud cover is high, the fall time for the snow crystal is long and the temperatures are a few degrees below zero with relatively dry air, we got the perfect powder light snow skiers are looking for (Clung & Schaerer, 2006;47, Landrø, 2007;35).


References:

Mc Clung, D & Schaerer, P.(2006). The Avalanche Handbook 3rd Edition, The Mountaineers Book, USA.

Landrø, M.(2007). Skredfare - En håndbok om skred for fjellskiløpere, klatrere og løssnøkjørere, Fri flyt, Oslo.

Wergin, P. W; Rango A; Foster, J; Erbe, F. E; Pooley, C.(2002).Retrieved from: http://modis-snow-ice.gsfc.nasa.gov/uploads/pap_R_irreg02.pdf, 21.10.2011.

Glacier Course

After last weeks glacier course from the 18th to the 23rd of september at Jostedalen, I grew interest in the high frequency climate changes that have been occurring in the quaternary period of our time scale. At about 5.000 years ago the climate started cooling down and developed new glaciers after a warm period. The maximum of the "little ice age" was year 1750, since that time they have generally been withdrawing. There are several theories however none are quite sure why these phenomenon appears (Haslene, 2008 & Nesje, 1995). Three of them are described briefly in the text bellow.

The Three Theories

Sunspots

The solar radiation increase with a growing number of sunspots. The climatic effect is barley measurable in a 11 year cycle, but there have been three  periods with notably low activity during the last 1000 years; 1280-1350, 1416-1534 and 1654-1714 which is the high of the last ice age(Nesje, 1995).

The Tufte Glacier, Jostedalen

Volcanic Eruptions

Explosive eruptions can cover the stratosphere with silica particles and gases that absorbs the shortwave radiation. The stratospheric winds diverge the particles over the entire planet and they can last to at least 2 years. This can lower the yearly temperature by 1 degree.  There have been several incident like the year with no summer in 1816 related to the Mt.Tambora eruption(Rampino & Self, 1982).

Greenhouse Gasses

50% of the suns radiation absorbs in the atmosphere, while the rest break through and heats up the earth. The average temperature is around 15 degrees and will alternate if the balance of the gases in the atmosphere changes. Analysis 160.000 years back of the Arctic shows the temperature variations corresponding to the carbon and methane gases in the atmosphere(Karl, Knight & Plummer, 1995 & Nesje, 1995).

New Ice Age

I am not a scientist, and there are a lot of different theories. However, looking at the oncoming eruptions from Iceland and our ever increasing needs for more fossil fuels and waste on the earth and in the atmosphere I am not sure if there is an future ice age approaching, but everything seams to lead that way.

References:

Nesje, A.(1995). Brelære. Høyskoleforlaget, Kristiansand.

Haslene, S.(2008). Breboka - Håndbok i brevandring. DNT fjellsport, Oslo.

Rampino, M. R. & Self, S.(1982). Retrieved from:
http://www.sciencedirect.com/science/article/pii/0033589482900655(20.00, 30.09.11)

Karl, T. R, Knight, R. W. & Plummer, N.(1995). Retrieved from: http://www.nature.com/nature/journal/v377/n6546/abs/377217a0.html(16.28, 26.09.11)