Daily Archives: 4 March 2011

27 February 2011 Grainola, Oklahoma tornado

My chase partners on this day were Dan Dawson and Jana Houser. We were attracted to the area around Enid, Oklahoma as an initial target, because of the strong shear, a narrow corridor of CAPE, and an incipient dryline push indicated in the models (SPC outlook). We intercepted a strengthening cell near Pond Creek, Oklahoma around 5:20 p.m. The reflectivity from KICT (KVNX was down for its polarimetric upgrade) showed a persistent, 60+ dBZ core, so we assume there was hail present.

Storm motions were ENE at 45-55 mph. As we jogged east and then north from Lamont, the cloud base began to lower. The first one quickly bowed out and became a “whale’s mouth”, indicating that a cold downdraft had reached the surface and begun to spread out toward us. Gradually, however, as we passed through Blackwell on OK-11, the storm, now clearly a supercell on radar, began to recover and developed a clear slot on its west side. We continued east in order to keep pace with the storm.

Near Kidare, the paved road T-ed off, and we had to make a choice whether to go north a few miles to Newkirk to keep the base within visual range, or south three miles to continue east on OK-11 through Kaw City. I was driving, so that choice was primarily the responsibility of my chase partners. While most other chasers turned north at the intersection of OK-11 and U.S. Hwy. 77, we turned south, and then continued east across the Kaw Lake Dam. Our view toward the base of the storm now blocked, we began to hear tornado warnings for the storm coming from three different CWAs (Tulsa, Norman, and Wichita) and questioned whether we had made the right decision.

However, as we emerged from the depression around Kaw Lake, we started to see suspicious appendages under the cloud base. It being February, it was close to sunset (around 6:20 p.m.), so the contrast wasn’t great. We turned north on OK-18 at Shidler, Oklahoma; the video sequence above records what we saw after emerging from the north side of that town. One particular appendage caught and held our attention. From a distance, it could have been mistaken for a scud finger, but as we drew closer, its persistence and tapered, conical shape made clear that it was a funnel cloud. In the video, you can hear us debating for a minute or two whether what we’re seeing is a tornado, or not. The funnel never made contact with the ground, but I did note a few puffs of red dirt underneath it.

After the white cone became occluded and dissipated, my chase partners noted a continuation of the tornado in the form of a dust tube extending from the ground to cloud base off to our east. I was still driving and unable to film this phenomenon; however my chase partners documented it.

We continued north on OK-18 until we crossed the Kansas border. At no point did we note crossing a surface damage track; however, it was dark, so we might have missed seeing some damage. As of this writing, I am not aware of a damage survey for this tornado; however, the SPC preliminary report notes an EF-0 rating.

We turned east on U.S. Hwy 166, following the storm as it produced an additional lowering illuminated by lightning. However, this lowering dissipated after a few minutes. We called off the chase near Sedan, Kansas, on account of darkness.