TWO YEARS AGO: THE MARSHALLTOWN EF-3 TORNADO

On July 19th, 2018 multiple tornadoes touched down in central Iowa.

That included twin twisters in Bondurant, an EF-3 in Pella and the EF-3 that went into the heart of Marshalltown.

It's a radar image you don't see all that much in this neck of the woods. A clear hook echo and a TDS (tornado debris signature) showing evidence of a tornado and a large tornado at that. It formed after the storm producing the tornado in Pella (to the south) sent out an outflow boundary. The boundary fed the storm (essentially) and lead to stronger rotation that produced a large tornado that formed just outside of the city.

A rare Tornado Emergency was issued for Marshalltown, the National Weather Service saying a large tornado would produce "catastrophic" damage. The NWS survey would estimate winds at 144 mph.

Picture from Denise Pelster:

Pictures from Aaron Gerhardt: