Biggest tornado outbreak in Twin Cities history came May 6, 1965

“You kids get inside. Your father called and there’s a tornado coming!”

Those words from my mom are etched into my memory from 59 years ago this Monday. It’s my first living memory.

We were picking up hailstones the size of my fist with football helmets under an iridescent green sky. The F4 tornado tore through neighborhoods a half mile from my Deephaven home.

When we saw the damage the next day, I knew I had to find out what caused this. A meteorologist was born that day.

It was the first time civil defense sirens were used during tornadoes.

Here is more on the 1965 tornado outbreak from the Twin Cities National Weather Service office:

May 6, 1965 was one of the worst tornado outbreaks in Minnesota history. Six tornadoes affected six counties around the Twin Cities with 13 fatalities and over 500 injured. The tornado outbreak lasted three hours and caused $51 million in damage. There were four F-4s, one F-3, and one F-2. Two of the F-4s crossed paths, causing even more damage. These tornadoes developed due to low pressure in North Dakota/Canada and unstable air behind a warm front over the Twin Cities region.

Environment

On the morning of May 6, two upper-level low pressure systems were situated over the western U.S. and the North Dakota/Canada border. The flow/circulation associated with these lows created favorable conditions for instability. Later in the evening, warm moist air was located behind the warm front over the Twin Cities area. This environment led to convection and tornadic supercells.