United States
tsunamis, volcanoes, and earthquake activity around
Pacific Basin; hurricanes along the Atlantic and Gulf of Mexico
coasts; tornadoes in the midwest and southeast; mud slides in
California; forest fires in the west; flooding; permafrost in
northern Alaska, a major impediment to development

United States Pacific Island Wildlife Refuges
Baker, Howland, and
Jarvis Islands: the narrow fringing reef surrounding the island can
be a maritime hazard
Kingman Reef: wet or awash most of the time, maximum elevation of
less than 1 m makes Kingman Reef a maritime hazard
Midway Islands, Johnston, and Palmyra Atolls: NA

Uruguay
seasonally high winds (the pampero is a chilly and
occasional violent wind that blows north from the Argentine pampas),
droughts, floods; because of the absence of mountains, which act as
weather barriers, all locations are particularly vulnerable to rapid
changes from weather fronts

Uzbekistan
NA

Vanuatu
tropical cyclones or typhoons (January to April); volcanic
eruption on Aoba (Ambae) island began 27 November 2005, volcanism
also causes minor earthquakes; tsunamis

Venezuela
subject to floods, rockslides, mudslides; periodic droughts

Vietnam
occasional typhoons (May to January) with extensive
flooding, especially in the Mekong River delta

Virgin Islands
several hurricanes in recent years; frequent and
severe droughts and floods; occasional earthquakes

Wake Island
occasional typhoons

Wallis and Futuna
NA