14 June 2011: Norman, OK high wind and hail event

This video pretty much summarizes the story.

Phased array with rain shaft. Looks innocuous enough.

Phased array with rain shaft. Looks innocuous enough.

Dan and I noticed a high-based updraft producing a slender precipitation shaft as we left the NWC yesterday around 6:30 p.m. We decided, on the spur of the moment, to grab our camera gear from the house and head over to North Base to shoot some time lapse near the radar forest.

RaXPol deployed at North Base in anticipation of the coming storm.

RaXPol deployed just as the rainfoot surged out toward us.

As we were taking video and photos, RaXPol pulled up nearby, so we went over to them. As they began to collect volume scans, the precipitation shaft swelled out a the base and rushed out toward us. We witnessed rotor clouds and ascending rain curtains just ahead of it, before becoming engulfed.

Hangar door debris at North Base

This hangar door blew over 200' from its track to rest in this field. Most of the corrugated metal covering blew away.

For about seven minutes, we experienced bursts of heavy rain, quarter-to-golf ball-sized hail, car-rocking winds, and near-zero visibility. We also saw pieces of metal debris fly across the field from the direction of Max Westheimer Airport. (Later, we figured out that they were from a hangar door that blew off.) We had to shout to be heard over the din of the hail battering the outside of my car. Jackrabbits and a skunk went dashing downwind past us. Nearby ditches and culverts quickly filled with water, and leaves and branches tumbled across the fields.

Social media updates told us of fences blown down, power outages, chimneys partially collapsed, roof shingles peeled away, and lawn furniture either vanishing or appearing where it shouldn’t be. We noted that the damage sounded much worse on the east side, and, having looked at some photos and video from friends of mine who live over there, I believe it!

Norman meteogram from 6/14/11

Norman meteogram from 6/14/11. Note the wind spike and other changes at 7:30 p.m. CDT.

The Norman Mesonet meteogram tells most of the story; we were parked just across the field from the station. This event was not entirely a surprise – We were in an SPC slight risk area for convective weather, primarily owing to the threat of strong winds and hail. I may have jumped the gun by labeling this a “microburst” when I uploaded my video; evidently NWS is avoiding that terminology until they do a damage survey. The velocity presentation from the Will Rogers TDWR, however, showed a semi-circular gust front surging toward Norman from the storm in question.

Update: NWS is now characterizing this event as a downburst. You can read their write-up here. They even link to a couple of my photos and video!
Update: My video was also used in an episode of SUNUP TV, an OK State production with a segment provided by the Oklahoma Mesonet, that airs on our local PBS affiliate OETA. Funny thing is, when they requested permission to use the video, I sent them raw clips without the watermark, but what ended up on the air was taken straight off YouTube and still has the watermark. Oh, well!
This video also made YouTube Trends as one of the most viewed in Oklahoma. The two clips on that site are from other people (the first is Mike Coniglio’s, the second from Tornado Titans), but there’s also a link to mine in the end text.