__________________ can be devastating: water supplies dry up, crops fail to grow, animals die and malnutrition and ill health become widespread.

• Avalanche

• Flood

• Drought

• Landslide

_____________________ brings very violent winds, torrential rain, high waves and, in some cases, very destructive storm surges and coastal flooding.

• Tornadoes

• Heavy rain

• Mudslides

• Tropical Cyclone

______________________ reduce visibility and air and road traffic can be disrupted. Smog, acid rain, the ozone hole and an adverse increase in the greenhouse effect are also caused by air pollution. Stable atmospheric conditions often lead to a concentration of pollutants in urban and industrial areas where there are significant emissions.

• Floods

• Air Pollution

• Sand Storms

• Dust Storms

_________________ inflict damage in Africa, the Middle East, Asia and southern Europe. When weather and ecological conditions favour breeding, the insects are forced into a small area. They stop acting as individuals and start acting as a group. Within a few months, huge swarms form and fly with the wind in search of food. Swarms can be dozens of kilometres long and travel up to 200 km a day. A small part of an average swarm (or about one tonne of locusts) eats the same amount of food in one day as 10 elephants or 25 camels or 2 500 people.

• Desert locusts

• Tropical Cyclone

• Mudslides

• Landslides

______________ and _____________________ can also occur after a period of dry conditions when moderate or heavy rain falls onto very dry, hard ground that the water cannot penetrate. Floods come in a number of forms, from small flash floods to sheets of water covering extensive areas of land. They can be triggered by severe thunderstorms, tropical cyclones, large low pressure systems , monsoons, ice jams or melting snow.

• Flood

• Flash Flood

• Landslide

• Mudslide

__________________ / _____________________ are local events and usually unexpected. They occur when heavy rain or rapid snow or ice melt or an overflowing crater lake loosens vulnerable parts of the landscape on steep slopes, resulting in large amounts of earth, rock, sand or mud flowing swiftly down slope. Hillsides or mountain sides that  are bare or have had their vegetation cover degraded  through clearance or by forest or brush fires may be especially at risk.

• Mudslide

• Landslide

• Avalanche

• Flood

__________________ is a mass of snow and ice falling suddenly down a mountain slope, often taking earth, rocks and rubble with it.

• Landslides

• Mudslides

• Flash Floods

• Avalanche

____________ / _______________ usually occur when strong winds lift large amounts of sand and dust from bare, dry soils into the atmosphere. Over the last decade, scientists have come to realize the impacts on climate, human health, the environment and many socio-econimic sectors. WMO Members are at the vanguard in evaluating these impacts and developing products to guide preparedness, adaptation and mitigation policies. 

• Dust Storms

• Lightning

• Sand Storms

• Tornadoes

____________________ Heat waves are most deadly in mid-latitude regions during the warmer months of the year. They are characterized by a number of days in a row where the temperatures are significantly above the long term average both day and night. The oppressive air mass in an urban environment can result in many deaths, especially among the very young, the elderly and the infirm. In 2003, much of western Europe was affected by heat waves during the summer months. In France, Italy, The Netherlands, Portugal, Spain and the United Kingdom, they caused some 40 000 fatalities. Extremely cold spells are also dangerous causing hypothermia and aggravating circulatory and respiratory diseases in those vulnerable to this risk.

• Duststorms

• Sandstorm

• Lightning

• Thermal Extremes

______________/______________/___________ All thunderstorms give rise to sudden electrical discharges in the form of lightning and they often bring rain and gusty winds. Severe thunderstorms are associated with all or combinations of heavy rain,  large hail, very strong winds and occasionally tornadoes or snow. Tornadoes are particularly common in the Great Plains of North America but they can and do occur anywhere, especially in temperate latitudes. Their extremely strong rotating winds can cause severe damage. Other associated phenomena include extremely strong winds from downbursts and flash floods. Worldwide, lightning during dry periods is a significant factor in starting wildfires in forests and grasslands.

• Thunder Storms

• Lightning

• Tornadoes

• Wild Fire