GEOG220 Lecture 20: Severe Weather
18 May 2018
School
Department
Course
Professor
Ball Lighting
● Glowing ball of light
● Rare
● Comes through their window, and quietly goes out or explodes
● Seems to be drawn to closed spaces
○ Sometimes aircrafts
Lightning
● major cause of forest fires, brush fires, and even house fires
● On average about 50 persons killed each year by lightning and 100s are injured
○ Been going, due to faster and better treatment
● Lighting strikes
○ Under trees (25%)
○ Open areas and high elevations (includes sports fields, and goldfing) 51%
○ Water (swimming fishing, boating) 14%
○ farm & heavy equipment 5%
○ Telephone 4%
○ Radio equipment 1%
Hail
● 1” hail all east of rocky mountains - because gulf of mexico moisture meets arctic and
creates dividing line
● Can come anytime of the year but normally late spring and early summer
● Majority of large hail falls in great plans and high plans of the US
○ Almost more than anywhere else in world
○ Northern India also has hail
● Formed by repeated movement below and above freezing level
● Onion like freezing structure
● Stones can range from pea size to softball
● Size of a .4” hail is size of ladybug falls at 20mph
● Sky sometimes looks greenish when relatively large hail storm is falling
● Can be different sizes, not just spherical
Severe convection winds
● Straight winds create more damage
● Due to more of these winds
● Greater than 58 mph
● Same area as where hail is found
● Microburst or downburst is a strong damaging downdrafts within a thunderstorm and
often confused with tornados
○ no rotation
○ Usually only a km across or less and wind speeds must be 58 mph or higher to
be classified as a “severe” convection wind
○ also associated with downdraft
Tornados
● By far US has more tornadoes than anywhere else combined
Document Summary
Comes through their window, and quietly goes out or explodes. Seems to be drawn to closed spaces. Major cause of forest fires, brush fires, and even house fires. On average about 50 persons killed each year by lightning and 100s are injured. Been going, due to faster and better treatment. Open areas and high elevations (includes sports fields, and goldfing) 51% 1 hail all east of rocky mountains - because gulf of mexico moisture meets arctic and creates dividing line. Can come anytime of the year but normally late spring and early summer. Majority of large hail falls in great plans and high plans of the us. Almost more than anywhere else in world. Formed by repeated movement below and above freezing level. Stones can range from pea size to softball. Size of a . 4 hail is size of ladybug falls at 20mph. Sky sometimes looks greenish when relatively large hail storm is falling.
