A small, recent cluster of meteorite craters, the largest of which is called Kaali are found near Saaremaa, Estonia. It is thought that the impact was witnessed by the Iron Age inhabitants of the area.
°C (61.3 °F) on the Baltic islands to 17.1 °C (62.8 °F) inland in July, the warmest month, and from −3.5 °C (25.7 °F) on the Baltic islands to −7.6 °C (18.3 °F) inland in February, the coldest month. Precipitation averages 568 mm (22.4 in) per year and is heaviest in late summer.
Estonia's land border with Latvia runs 267 km (166 mi); the Russian border runs 290 km (180 mi). From 1920 to 1945, Estonia's border with Russia, set by the 1920 Tartu Peace Treaty, extended beyond the Narva River in the northeast and beyond the town of Petseri in the southeast. This territory, amounting to some 2,300 km2 (888 sq mi), was incorporated into Russia by Joseph Stalin at the end of World War II.
Environmental issuesOne of the most burdensome legacies of the Soviet era is widespread environmental pollution. The worst offender in this regard was the Soviet army. Across military installations covering more than 800 km² of Estonian territory, the army dumped hundreds of thousands of tons of jet fuel into the ground, improperly disposed of toxic chemicals, and discarded outdated explosives and weapons in coastal and inland waters. In the 1990s, during the army's withdrawal from Estonia, extensive damage was done to discarded buildings and equipment. In October 1993, the Estonian Ministry of Environment issued a preliminary report summing up part of the degradation it had surveyed thus far. The report described the worst damage as having been done to Estonia's topsoil and underground water supply by the systematic dumping of jet fuel at six Soviet army air bases. At the air base near Tapa, site of the worst damage, officials estimated that six square kilometers of land were covered by a layer of fuel; 11 square kilometers of underground water were said to be contaminated. The water in the surrounding area was undrinkable. With Danish help, Estonian crews began cleaning up the site, although they estimated the likely cost to be as much as 4 million EEK. The Ministry of Environment assigned a monetary cost of more than 10 billion EEK to the damage to the country's topsoil and water supply. However, the ministry was able to allocate only 5 million EEK in 1993 for cleanup operations.
In a 1992 government report to the United Nations Conference on the Environment and Development, Estonia detailed other major environmental concerns. For instance, for several consecutive years Estonia had led the world in the production of sulfur dioxide per capita. Nearly 75% of Estonia's air pollution was reported to come from two oil shale-based thermal power stations operating near Narva. The mining of oil shale in northeastern Estonia has also left large mounds of limestone tailings and ash dotting the region. Near the town of Sillamäe, site of a former uranium enrichment plant, about 1,200 tons of uranium and about 750 tons of thorium had been dumped into a reservoir on the shore of the Gulf of Finland. This was said to have caused severe health problems among area residents. In the coastal town of Paldiski, the removal of waste left by Soviet army nuclear reactors was also a major concern. The combined cost of environmental cleanup at both towns was put at more than EKR3.5 billion.
Natural hazards: flooding occurs frequently in the spring in certain areas.