Simple Thunderstorm Hazards
Downbursts and Gust Fronts
downburst: violent downdraft
caused by thunderstorms “exhaust” (cool and dry descending air)
when a downburst hits the ground, it moves laterally as a gust front
if over loose sediment (like sand, silt) they become sandstorms or haboobs
haboob: dust cloud within a gust front
Hail
layered balls of ice
formed by updrafts and rapid condensation (desublimation) inside thunderstorms
require:
large thunderstorms with buoyant, warm, moist air
mid- and upper-level freezing cold air (maximum temperature contrast) which results in…
strong updrafts to keep hail suspended in cloud while adding coatings of ice
occurs in largest storms with the greatest temperature variation
largest variation makes strong updrafts that keep hail aloft and more layers are added
leads to baseball/grapefruit-sized hail
Heavy Rain/Flash-floods
thunderstorms occur in dry areas
heavy rains overload local drainage systems
cause flash floods
Simple Thunderstorm Hazards
Downbursts and Gust Fronts
downburst: violent downdraft
caused by thunderstorms “exhaust” (cool and dry descending air)
when a downburst hits the ground, it moves laterally as a gust front
if over loose sediment (like sand, silt) they become sandstorms or haboobs
haboob: dust cloud within a gust front
Hail
layered balls of ice
formed by updrafts and rapid condensation (desublimation) inside thunderstorms
require:
large thunderstorms with buoyant, warm, moist air
mid- and upper-level freezing cold air (maximum temperature contrast) which results in…
strong updrafts to keep hail suspended in cloud while adding coatings of ice
occurs in largest storms with the greatest temperature variation
largest variation makes strong updrafts that keep hail aloft and more layers are added
leads to baseball/grapefruit-sized hail
Heavy Rain/Flash-floods
thunderstorms occur in dry areas
heavy rains overload local drainage systems
cause flash floods