Where tornadoes have been clustered this year

Tornado count

1-2

3-4

5-8

9-14

15+

Note: Figures represent preliminary reports in the contiguous United States that are labeled as "tornado" and are not confirmed tornadoes. They are filtered by geographic proximity to avoid duplicated events and have been aggregated and counted within hexagons placed in a 25-mile grid over the United States.

Source: NOAA Storm Prediction Center

Map: Matt Stiles and Renée Rigdon, CNN