Severe Weather
Severe weather occurs frequently in the DFW metroplex. Whether it is thunderstorms, lightning, extreme heat, or winter weather, residents need to be prepared for all of these hazards.


A tornado can occur at any time of the year, but spring and summer are considered tornado season in North Texas. While tornadoes can happen at any time of day, they are more likely to occur between 3-9pm.

What is the difference between a watch and a warning?

~ A severe weather watch is issued by the National Weather Service when conditions are favorable for severe weather to develop.

~ A severe weather warning is issued by the National Weather Service when severe weather has been detected in an area either by radar indicators or trained storm spotters.

Operational Enhanced Fujita Scale

EF Number
3 Second Gust (MPH)
0 65-85
1 86-110
2 111-135
3 136-165
4 166-200
5 Over 200
What is the difference between flash flooding and flooding?

~Flash flooding occurs during heavy rain events and happens very quickly and ends just as quickly.

~Flooding occurs as the result of a prolonged rain event or lake/creek overflow. It is more gradual and more predictable.

Dam/Levee failure may result in flash flooding or flooding.


Hail is formed when water droplets are carried in updrafts within a storm to a height in the sky where freezing occurs. These ice particles continue to grow as they may be dropped and picked up again, adding another layer of ice. Eventually, the hail becomes to heavy and falls to the ground.

A diameter of .75 inch or greater, is considered to be severe.

Hail size estimates
  • Pea = 1/4 inch diameter
  • Marble/Mothball = 1/2 inch diameter
  • Dime/Penny = 3/4 inch
  • Nickel = 7/8 inch
  • Quarter = 1 inch
  • Ping pong ball = 1 ½ inches
  • Golf ball = 1 ¾ inches
  • Tennis Ball = 2 ½ inches
  • Baseball = 2 ¾ inches
  • Tea cup = 3 inches
  • Grapefruit = 4 inches
  • Softball = 4 ½ inches

Dallas County Hazard Mitigation Action Plan