Thunderstorms

Thunderstorms happen year-round in Arizona, but they are most common during the monsoon season (mid-June through September).

Severe thunderstorms can produce heavy rain, flash flooding, severe winds, hail, and lightning. Lightning continues to be one of the top three storm-related killers in the United States. According to the National Climatic Data Center, lightning has caused 17 deaths and 82 injuries in Arizona since 1996. Although most lightning victims survive, people struck by lightning often report a variety of long-term, debilitating symptoms.

Dry thunderstorms that do not produce rain that reaches the ground are most prevalent in the western United States. Falling raindrops evaporate, but lightning can still reach the ground and can start wildfires. Thunderstorms can produce high winds, heavy rains and lightning, but there are ways to stay safe.

• ​ BE Prepared
• TAKE Action
• BE Informed

BE Prepared

Thunderstorm Basics

• They may occur singly, in “clusters” or in “lines.”
• Some of the most severe thunderstorms affect one location for an extended time.
• Thunderstorms typically produce heavy rain for a brief period lasting from 30 minutes to an hour.
• Warm, humid conditions are highly favorable for thunderstorm development.
• About 10 percent of thunderstorms are classified as severe (or one that produces hail at least an inch or larger in diameter, has winds of 58 miles per hour or higher, or produces a tornado.)

Lightning Basics

• Lightning’s unpredictability increases the risk to individuals and property.
• Lightning often strikes outside of heavy rain and may occur as far as 10 miles away from any rainfall.
• “Heat lightning” is actually lightning from a thunderstorm too far away from thunder to be heard.
• Most lightning deaths and injuries occur when people are caught outdoors in the summer months during the afternoon and evening.
• The chances of being struck by lightning are estimated to be 1:600,000 but can be reduced by following safety precautions.
• Lightning strike victims carry no electrical charge and should be attended to immediately.

TAKE Action

Lightning Safety When Outdoors

During Thunderstorms and Lightning

If thunderstorm and lightning are occurring in your area, you should:

• Stay tuned to NOAA Weather Radio, commercial radio or television for updates.
• Avoid contact with corded phones and devices including those plugged into electric for recharging.  Cordless and wireless phones not connected to wall outlets are OK to use.
• Avoid contact with electrical equipment or cords. Unplug appliances and other electrical items such as computers and turn off air conditioners. Power surges from lightning can cause serious damage.
• Avoid contact with plumbing. Do not wash your hands, take a shower, wash dishes, or do laundry.
• Stay away from windows and doors, and stay off porches.
• Do not lie on concrete floors and do not lean against concrete walls.
• Avoid natural lightning rods such as a tall, isolated tree in an open area.
• Avoid hilltops, open fields, the beach or a boat on the water.
• Take shelter in a sturdy building. Avoid isolated sheds or other small structures in open areas.
• Avoid contact with anything metal (e.g., farm equipment, motorcycles, golf and clubs, and bicycles).
• If you are driving, try to safely exit the roadway and park. Stay in the vehicle and turn on the emergency flashers until the heavy rain ends. Avoid touching metal or other surfaces that conduct electricity in and outside the vehicle.

After a Thunderstorm or Lightning Strike

If lightning strikes you or someone you know, call 9-1-1 for medical assistance as soon as possible. The following are things you should check when you attempt to give aid to a victim of lightning:

• Breathing—if the victim has stopped breathing, begin mouth-to-mouth resuscitation.
• Heartbeat—if the victim’s heart has stopped, administer CPR.
• Pulse—if the victim has a pulse and is breathing, look for other possible injuries. Check for burns where the lightning entered and left the body. Also be alert for nervous system damage, broken bones and loss of hearing and eyesight.

After the storm passes remember to:

• Never drive through a flooded roadway. Turn around, don’t drown!
• Stay away from storm-damaged areas.
• Listen to a NOAA Weather Radio or to local radio and television stations for updated information or instructions, as access to roads or some parts of the community may be blocked.
• Help people who may require special assistance, such as infants, children, the elderly, and individuals with access or functional needs.
• Stay away from downed power lines and report them immediately.
• Watch your animals closely. Keep them under your direct control.

BE Informed

• Learn about the emergency plans that have been established in your area. 
• Familiarize yourself with these terms to help identify a thunderstorm hazard:
  
  • Severe Thunderstorm Watch—Tells you when and where severe thunderstorms are likely to occur. Watch the sky and tune to local radio or television for information.
  • Severe Thunderstorm Warning—Issued when severe weather has been reported by spotters or indicated by radar. Warnings indicate imminent danger to those in the path of the storm.
• Research additional information about thunderstorm, beginning with the following resources.
  
  • Facts about Lightning
  • How to Guides to Protect Your Property or Business from High Winds
  • National Weather Service

(source: Ready.gov)