This cell was in Clark County, IA on the evening of June 4, 2008. Trevor Black and I were located east / northeast of Murray, IA on 150th Avenue about 1 to 1 ½ miles north of IA 34. We did hear storm sirens sounding and we believed it was from Murray. We videotaped the storm for about 17 minutes (approximately 10:05 p.m. to 10:22 p.m.) until the funnel roped out. Storm motion was awesome for chasing! The camera direction is to the northwest. Storm motion was from photo left to right. We were not 100% certain the tornado was on the ground, however, the close proximity of the funnel to the ground indicated to us that there had to be some ground action.
We repositioned north of Osceola, IA on I-35 to see if a new funnel would spin up but we never saw a new one. We did watch the rotating wall cloud cross the interstate. Several cars also observed it and pulled to the shoulder and stopped. We pulled off the storm a little NE of here to beat the linear mess that was approaching from the west.
Meteorologist Jon Davies review of the storm:
Here's a list of tornadoes from NWS Storm Data that came from that supercell... you can make sure Corey gets this, if he's interested
Starting at at 6:55 pm CDT:
EF2? near Emerson IA (Mills Co.) 5-10 mi path? at least two homes badly damaged (Omaha NWS final data not completed yet).
EF0 near Nodaway IA (Adams Co.) 2 mi path no damage
EF1 near Brooks & Mercer IA (Adams Co.) 9 mi path $20,000 damage
EF1 near Corning IA (Adams Co.) 6 mi path $50,000 damage
EF0 near Kent IA (Union Co.) 1 mi path $5000 damage
EF1 near Creston IA (Union Co.) 4 mi path $55,000 damage
EF1 near Afton & Murray IA (Union-Clarke Co.) 11 mi path $5000 damage (this looks like the one you and Corey were on)
Ending at ~10:25 pm CDT
None of the tornadoes besides the first looks like it did much more than power pole, tree, and minor farmstead damage.Des Moines NWS may not have done an actual survey (NWS often doesn't do ground surveys unless there are indications that the tornadoes are EF2 or greater intensity). It looks like they relied mainly on local reports and information relayed to them. You're right, anytime you see a condensation funnel consistently more than 1/2 way to the ground, it is probably a tornado. That sure looks like the case with what you were watching.
An interesting storm... Thanks for sharing the images! A very good storm chase...Jon
