NWS has completed their storm survey and this is what they found:
That matches the intensity of the 2008 tornado in Vancouver. Also similar to the Longview tornado back in October last year.
So the Aumsville storm from December 2010 remains the strongest in our area since 1972. It was rated an EF-2
A very obvious question comes from our viewers; why aren’t these forecast ahead of time and/or why no warnings in the minutes before?
- These are relatively weak tornadoes and the circulation is often weak. I checked today’s radar imagery and I don’t see anything that sticks out. At least no more shear than we see with our typical cold showers/thundershowers. There is no big “hook echo” to look for like with the big storms.
- Portland’s radar is located at 2,000′. The radar beam goes up in elevation the farther you get from that location. As a result we don’t see the lowest 3,000′ or so in the metro area, and nothing under about 10,000′ once you get to Eugene or up around Olympia. Most of the action is happening closer to the surface so it can’t be seen.
Here’s a look at the ranking of our recent tornadoes:
Chief Meteorologist Mark Nelsen