Earthquake
An earthquake (also known as a quake, tremor or temblor) is the result of a sudden release of energy in the Earth's crust that creates seismic waves.
Tsunami
A tsunami also called a tsunami wave train, and at one time incorrectly referred to as a tidal wave, is a series of water waves caused by the displacement of a large volume of a body of water, usually an ocean, though it can occur in large lakes.
Tornado
A tornado (often referred to as a twister or, erroneously, a cyclone) is a violent, dangerous, rotating column of air that is in contact with both the surface of the earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud.
Floods
A flood is an overflow of an expanse of water that submerges land. The EU Floods directive defines a flood as a temporary covering by water of land not normally covered by water
Volcanic Eruptions
Volcanoes can cause widespread destruction and consequent disaster through several ways. The effects include the volcanic eruption itself that may cause harm following the explosion of the volcano or the fall of rock.
European Avalanche RiskTable
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In Europe, the avalanche risk is widely rated on the following scale, which was adopted in April 1993 to replace the earlier non-standard national schemes. Descriptions were last updated in May 2003 to enhance uniformity.
In France, most avalanche deaths occur at risk levels 3 and 4. In Switzerland most occur at levels 2 and 3. It is thought that this may be due to national differences of interpretation when assessing the risks.
| Risk Level | Snow Stability | Flag | Avalanche Risk |
|---|---|---|---|
| 1 - Low | Snow is generally very stable. |  | Avalanches are unlikely except when heavy loads are applied on a very few extreme steep slopes. Any spontaneous avalanches will be minor (sluffs). In general, safe conditions. |
| 2 - Limited | On some steep slopes the snow is only moderately stable. Elsewhere it is very stable. | | Avalanches may be triggered when heavy loads are applied, especially on a few generally identified steep slopes. Large spontaneous avalanches are not expected. |
| 3 - Medium | On many steep slopes the snow is only moderately or weakly stable. |  | Avalanches may be triggered on many slopes even if only light loads are applied. On some slopes, medium or even fairly large spontaneous avalanches may occur. |
| 4 - High | On most steep slopes the snow is not very stable. | | Avalanches are likely to be triggered on many slopes even if only light loads are applied. In some places, many medium or sometimes large spontaneous avalanches are likely. |
| 5 - Very High | The snow is generally unstable. |  | Even on gentle slopes, many large spontaneous avalanches are likely to occur. |
[1] Stability:
- Generally described in more detail in the avalanche bulletin (regarding the altitude, aspect, type of terrain etc.)
[2] additional load:
- heavy: two or more skiers or boarders without spacing between them, a single hiker or climber, a grooming machine, avalanche blasting.
- light: a single skier or snowboarder smoothly linking turns and without falling, a group of skiers or snowboarders with a minimum 10 m gap between each person, a single person on snowshoes.
Gradient:
- gentle slopes: with an incline below about 30°.
- steep slopes: with an incline over 30°.
- very steep slopes: with an incline over 35°.
- extremely steep slopes: extreme in terms of the incline (over 40°), the terrain profile, proximity of the ridge, smoothness of underlying ground.
