The town of Parkersburg, Iowa, was devastated by an extraordinarily powerful tornado on Tuesday. The monster-sized funnel of the tornado reached one mile wide (1.6km), wrecked hundreds of homes and killed seven people.

The death toll would have been far higher though without a warning of the tornado. Several minutes beforehand, sirens sounded the alarm across the town. One couple dived under the staircase of their home and afterwards found a tree and a pickup truck on top of the stairs. In a local grocery store, staff and customers ran for shelter in the shop’s refrigerator room. Seconds later the tornado hit, leaving the refrigerator room intact and the survivors unharmed, but when they emerged afterwards they found the building destroyed, with a motorboat on top of the debris.

Many other tornados have torn through the Midwest this month, in what is the peak of the tornado season. But this year so far has been exceptional, with 1,191 tornados that have left at least 113 people dead. It is on course to beat the record for the largest number of tornados, which currently stands at 1,817 in 2004. Most worrying of all, though, is that the number of most powerful tornados this season has risen, and these seem to be hitting more populated areas.