Thunderstorms are rain-bearing clouds that produce lightning. On average, lightning injures 300 people and causes 80 fatalities in the United States each year. While most injuries and fatalities resulting from lightning occur when people are caught outdoors during the summer months, thunderstorms can occur anytime of the year. When you hear thunder, a storm is close enough to cause immediate danger. In fact, lightning can strike up to 10 miles outside of rainfall. In addition to lightning, other dangers associated with thunderstorms include strong winds, tornadoes, hail and flash flooding.

To prevent being caught in a thunderstorm and exposed to lightning:

• Check the National Oceanic and Atmospheric Administration (NOAA) and local weather reports for emergency notifications regarding thunderstorm activity and severe weather. 
• Consider rescheduling jobs to avoid being caught outside in severe weather conditions. 
• When working outdoors, continuously monitor weather conditions. Watch for darkening clouds and increasing wind speeds, which can indicate developing thunderstorms.

If weather reports and forecasts are calling for a thunderstorm and/or you hear thunder or see lightning, immediately seek shelter. NOAA recommends seeking out fully enclosed buildings with electrical wiring and plumbing. The interior wiring and plumbing will act as an earth ground. While sheltering from a thunderstorm, do not contact anything that can conduct electricity (e.g., electrical equipment or cords, plumbing fixtures, corded phones) and do not lean against concrete walls or floors (which may have metal bars inside). Remain in the shelter for at least 30 minutes after hearing the last sound of thunder. 

Training 

To access training on how to safely prepare for thunderstorms, the dangers associated with thunderstorms, and what to do when these dangers are present, click on the link below.

CALS Severe Weather Safety Training: Thunderstorms

Additional Resources

Ready.gov

Ready.gov/Wisconsin

OSHA Fact Sheet: Lightning Safety When Working Outdoors

CDC Natural Disasters and Severe Weather Webpage

OSHA Tornado Preparedness and Response Webpage