Tips & Facts

• For climatological purposes, the summer thunderstorm season runs from June 15 to September 30. This fixed date allows meteorologists to better compare one monsoon to the next.
• Tucson's average rainfall during the summer thunderstorm season is 6.06 inches. The wettest was an incredible 13.84 inches in 1964. The driest was only 1.59 inches in 1924.
• Arizona ranks Number 23 in lightning frequency among the lower 48 states and Washington DC.
• Even though Arizona rarely experiences a tornado, they do occur (an average of four every year). However, thunderstorm-generated winds can exceed 100 mph over a fairly large area, with the damage looking very much like tornado damage.

• Flash floods can occur many miles away from a storm.
• The vast majority of people killed in a severe storm or a flash flood are males.
• Most people killed in flash floods were in a vehicle.
• It is impossible to detect if a downed utility line is energized.

• It does not have to be raining for there to be a lightning risk. Lightning flashes do occur outside the rain area in thunderstorms, and especially in southern Arizona, there can be dry thunderstorms that produce lightning with no rain.
• Lightning activity varies greatly in southern Arizona. In a typical year, about ten times as many flashes occur in Nogales as in Phoenix.
• The most common locations to be struck by lightning are open fields or under trees.
• About 44 people each year are killed by lightning in the U.S. Ten times as many are injured.
• Lightning typically travels ten miles or less, however lightning has been documented to travel more than 60 miles from a thunderstorm.

• The vast majority of people killed in straight-line thunderstorm winds are struck by falling debris.
• 60-mph winds can lift the roof off a carport.
• 70-mph winds can turn a mobile home on its side if the mobile home is not anchored to the ground.
• 80-mph winds can lift the roof off a house.