Hail Size Estimates

(Diameter in inches)

 

Pea..................... 1/4 inch                           Golfball.......1 3/4 inch

 

Penny................. 3/4 inch                           Tennis Ball...2 ½ inch

 

Quarter............... 1 inch                              Baseball......2 3/4 inch

 

Half Dollar…1 1/4 inch                               Grapefruit...4 inch

 

Wind Speed Estimates

 

Speed (MPH)                            Effects

 

25-31................... Large branches in motion; whistling in telephone wires

 

32-38................... Whole trees in motion

 

39-54................... Twigs break off of trees; wind impedes walking

    

55-72................... Damage to chimneys and TV antennas; pushes over shallow rooted trees

 

73-112................. Peels surface off roofs; windows broken; trailer homes overturned

 

113+……………..Roofs torn off houses. Weak buildings & trailer homes destroyed; large trees uprooted.

Severe Thunderstorm Day

Monday, February 25, 2008

 

Severe thunderstorms can strike any time of the year.  Severe thunderstorms and tornadoes are more frequent in the spring months of March, April and May. 

Tennessee also has a "secondary" severe weather

season in November and December. Severe

thunderstorms can, and do, occur anytime of the day and night and during any month of the year.  Damaging

thunderstorm winds are much more common in

Tennessee than tornadoes. 

 

The National Weather Service defines a thunderstorm as “severe” when wind speeds reach 58 mph (50 kts) or stronger and/or 3/4 inch hail (or larger) falls from the storm.  Winds from severe thunderstorms can well exceed 100 mph, overturning trailers, unroofing homes, and toppling trees and power lines.  Most of the storm damage in the South is caused by “straight line winds” from thunderstorm downbursts. Severe Thunderstorm wind speeds may exceed the wind speeds of weak tornadoes.  All thunderstorms are capable of producing deadly lightning.

 

                

Severe Thunderstorm Safety Rules

 

FIND SHELTER IMMEDIATELY.  Go to a sturdy building that will withstand high winds.  Avoid electrical appliances, metal pipes and corded telephones.

When a Severe Thunderstorm Warning is issued for your location, treat it the same as

you would a Tornado Warning.  Remember that severe thunderstorms can produce damaging winds, large hail and deadly lightning.