On this date in 1999, a hot, muggy day on northern Minnesota’s Boundary Waters Canoe Area quickly changed into a devastating event. Thunderstorm winds increased to 100 mph as lawn chairs became tiny missiles.

Canoes and boats were blown into the air, followed by boat docks and uprooted trees. The storm lasted 20 minutes, knocking down 25 million trees, creating a flattened path 12 miles wide and 4 miles long.

Those who experienced this storm were amazed at the incredible wind speed that “swooped in and moved on.” What they experienced was a derecho, pronounced “de-ray-cho,” from the Spanish verb “tomar” meaning to turn or twist. A derecho is big, fast and produces damaging winds that blow in a straight line.

Fastcast: Late afternoon-evening showers.

Scattered showers, mainly after noon. Mostly sunny. High near 94. Calm winds becoming southerly at 5 mph. Rain chance: 40 percent. Tonight: 20 percent chance of showers. Low about 74.