Extreme Weather In Iceland: 

Wind Storms- 

Wind storms are common in Iceland. Storms there can often reach speeds in excess of 60 m/s. Extreme weather in Iceland. These storms rarely cause any significant damage on their own. Some secondary effects of these storms however are sea flooding and avalanches.

Iceland is kept warm by a branch of the gulf stream current that flows past the south and west shores. This warm current is Iceland's lifeblood, the reason the island enjoys warmer temperatures then it's northerly position might indicate. This does however create areas of pressure difference above the island, with cold air being drawn from the arctic to a low pressure center off of Iceland's east coast.  Iceland's average weather statistics.  These conditions feed high wind development across most of the island.

Snow storms-

Iceland does suffer from daunting, if not quite devastating, snowstorms. High winds and high levels of snowfall can cause massive transportation problems and cause people to remain in their homes for days at a time.  Snow storms in Iceland

Cyclones-
Extratropical cyclones are not unheard of in Iceland. The near constant area of low pressure on Iceland's east coast, the "icelandic low" as it's called, very regularly causes extratropical cyclones to form there, and sometimes make landfall on the island Icelandic cyclones

Subsidence in Iceland, a strange relationship.

Iceland doesn't have to worry about subsidence. Well, not in the usual sense. Soil subsidence is the movement of surface material, generally due to a change in conditions below the surface. A thick layer of soil above limestone, for example, can produce large movements of surface material, including sinkholes, when the underlying limestone is dissolved by weakly acidic water. Iceland has very little sedimentary rock (8-10%), and no large areas underlain by soluble rock. Rock history of iceland. The subsidence Iceland does have to worry about however, relates to volcanoes.

The image above is of the massive Bárðarbunga eruption from 2014-2015. This volcano erupted continuously for five months, from Sept. 2014 to Feb. 2015. In this time, and in the time since, the area inside of Bárðarbunga's caldera (the opening of the volcano) sank over 35 meters (115 feet) as the magma chamber emptied itself into a massive lava field on the surface. Detailed report of Bardarbunga caldera subsidence. The total subsidence for this event (the detailed measurement did not begin until the event had already started) is estimated at nearly 60 meters. The graph below shows this subsidence from Sept.-Mar. The eruption ended in mid February, and you can see that as the subsidence ceased, the line reversed very slightly. This shows that almost immediately upon cessation the magma chamber began to fill again.

Measuring the swelling or subsidence inside of volcanoes is a valuable tool for geologists trying to predict the health or volatility of a volcano. Subsidence during an eruption is self explanatory. If your volcano is subsiding with no visible eruption however, you must look for another reason, either that there is an eruption somewhere you can't see (such as into the sea or underground) or that the flow of magma which filled that chamber has gone elsewhere. If the flow of magma into a particular chamber does cease, a total collapse of the caldera may occur. This happened to the caldera of the Askja volcano after a massive eruption in 1875.  Askja caldera collapse. This particular event took over 40 years, and as such was not very dangerous, but a sudden collapse is possible and would pose a danger to any scientists unlucky enough to be studying the area at the time.

Mass Wasting, in it's many forms:

"Mass wasting" is a general term most people are unfamiliar with, but who's effects are very well known. Mass wasting is defined as "any type of downslope movement of earth materials." This can include land/rock slides, avalanche, or earth flows. Whatever the material involved, one constant in all of these events is a slope. Iceland is a very mountainous island. A large percentage of these slopes consist of loosely compacted volcanic materials. In addition, Iceland has significant snowfall in it's higher altitudes. These facts together mean that Iceland's most common forms of mass wasting are rock/land slides, and avalanches.

Landslide

Iceland suffers from landslides on a fairly regular basis. There was a significant slide into the caldera lake of the stratovolcano Askja in July of 2014, pictured here. 

While there was no loss of life, this slide was the largest recorded since the settlement of Iceland. Estimates place the volume of material displaced at 30-50 million cubic meters. Not all of this material went into the lake, but enough did to create a 20-30m (60-90ft) high tsunami all around the lake. Report on the Askja Landslide . It was very fortunate that this slide took place shortly before midnight, as people certainly would have been using the lake in daylight hours.


While a landslide may appear to humans to be a sudden, unpredictable event, this is not the case. Photographs from this and other slides show a gradual movement of large volumes of material over the course of years. This sudden movement was merely the culmination of many long years of instability. Any hillside should be treated as potentially hazardous, as all slopes are subject to the effects of gravity, and as such are always on their way down, to one extent or another.

Avalanche

 

As with any country with heavy snowfall and steep slopes, Iceland faces significant danger from Avalanche. Avalanche are caused by several factors in the snow. Sudden warming of snowpack on a slope can cause the upper levels to melt and saturate the lower layers with water, increasing the weight of the snow until it can no longer maintain it's position on the slope. Sudden rain onto existing snow will have the same effect. Wind blowing large quantities of snow onto the downwind side of a slope over a short time will also cause the mass of snow to become too great to maintain it's "angle of repose", the angle at which a mass can remain stationary on a slope. Avalanches are most common on slopes between 35 and 40 degrees. Grades below this lack the momentum necessary to create a dangerous flow, and grades above this tend to allow snow to constantly slide off. 

Read The Iceland Meteorological Office's section on avalanche here:

Danger Mitigation

Iceland recently commissioned a comprehensive study of all areas of avalanche risk. Iceland's Avalanche risk survey winds to a close. This initiative was started after two 1995 avalanches killed a total of 34 people in two towns in northern Iceland.  These tragic events highlighted both the underrated risk of avalanche in some areas of the country as well as the lack of preparedness for dealing with such events. After significantly increasing the collective knowledge of the Icelandic scientific community's understanding of avalanche risk and successfully developing a risk map and warning program for the island, the leftover funds from the assessment program are being redirected to increased mitigation of the effects of possible volcanic hazards.