Any meteorological event that poses a significant threat to life or property falls under the heading of severe weather. The category includes tornadoes, large hail, damaging straight-line winds, flash floods, blizzards, and intense heat or cold waves.

Criteria vary by region and by the specific hazard. In the United States, for example, a severe thunderstorm is defined by hail of one inch or larger, winds of 58 miles per hour or greater, or a tornado. Other countries use similar but not identical thresholds.

Warnings and watches are the primary tools for reducing risk. Advances in radar, satellite, and modeling have improved lead times, yet the public still needs to understand and act on the information. Education and resilient infrastructure further reduce impacts.

• Dangerous meteorological phenomena
• Includes storms, floods, extremes
• Defined by local criteria
• Mitigated by warnings and preparedness