Battle Ground Tornado: EF-1

December 10, 2015

NWS has completed their storm survey and this is what they found:

MarkTornado_TodayInfo

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

Aumsville Tornado_NWS-Damage_path

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?

Two answers

  1. 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.
  2. 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:

MarkTornado_Categories

Chief Meteorologist Mark Nelsen


Time For Another Tornado

December 10, 2015

It’s been 14 months since our last tornado within the FOX12 viewing area…must be time for another right?

Sure enough, at 11:10am a tornado hit Battle Ground.  Numerous videos make it pretty clear there was a defined circulation and I noticed from Air12 the trees were not all fallen in the same direction.

The NWS is out doing their storm survey and we’ll (hopefully) soon find out what the storm will be rated.  My guess would be EF-1.  But I’m no tornado damage expert by any means.

The last tornado was in Longview October 2014.  Here are the previous 3 tornadoes in our area:

Radar didn’t show anything too far out of the ordinary.  Some shear, some large hail, but nothing that screams TORNADO!  Most of our tornadoes are not seen by radar…either too far away (and below radar beam), or circulation is too weak at the beam elevation.

Interesting to note that once again we’ve seen a tornado in the “preferred tornado alley” downstream of the West Hills in Clark County.

Chief Meteorologist Mark Nelsen