Name this feature...

[Rebekah LaBar]

Hi everyone,

Last fall my family and I saw something rather strange-looking. My Mom and sister were quick to say it was tornado-like, but I wasn't quite sure what to think. At first I thought it might be a hail or rain shaft, but it was pretty narrow and started curving a bit. For a while the top was laying almost horizontal before it headed down and started curving. I took some digital photos while my sister took photos with film. My sister finally got her pictures developed and our debate over what this feature was arose again.

So, what do you think? Here are some photos of the feature and the clouds around it: http://s88.photobucket.com/albums/k175/lab...202005%20Storm/

I know these aren't the best photos; I tried scanning the prints, which were better, but the quality degraded considerably.

Here is what I know--
Date: October 1, 2005, ~6pm local time
Location: Central Washington, facing east (the Columbia River is just on the other side of those hills; this feature is probably directly over or very near the river)
Warnings: There was a severe thunderstorm warning issued about an hour earlier for the county just south of us; penny-sized hail was reported with this storm.

Two chasers have already suggested it could be a landspout, another told me it very well could be a hail shaft. At nearly 30 miles away, I obviously could not detect any rotation if it was occurring.

Thanks!

Rebekah

 

[Joe Zemek]

I'm lookin' at the cloud base; there seems to be a curved, slot-like component, and the curvature may indicate a weak area of vorticity, perhaps formed by outflow winds. The feature seems very narrow for precip.

 

[Stan Rose]

My guess is hail shaft; it looks a lot like many narrow hail shafts ive seen (pretty cool, tho). i suspect there was a fair amount of low lev wind shear, particularly given the river valley location, causing the curvurture.

 

[Bob Schafer]

It looks like a rain shaft to me. The curvature is irrelevant; caused by some weak undercutting. The storm doesn't look severe enough for that to even be hail.

 

[Susan Strom]

My vote is definitely for a little landspout with dust and mist inside. To me, the tube looks too perfect to be precip. High based precip looks wavy, like a veil, thicker at the top, thinner and uneven at the bottom as some of the precip evaporates as it descends. Plus the veil can blow around making it looks like a waving curtain, uneven at the sides too. The exception is when you have torrential rain and it's all coming down uninterrupted no matter what. That little tube looks like some of the F0 tornadoes, dust devils and mini-nadoes you see in Arizona.

Here are some precip veils in the desert. Rain and snow can look this way sometimes when the air has a certain dryness and the cloud bases are high.

 

[Brian Stertz]

Just looking at it...one might deduce a landspout but 2 things kind of say probably not. #1 the feature is 30 miles away, and #2 that cloud base is way to high with respect to the hills and ground. This would have to be a tremendous landspout to develop from that height and sustain for as long as the pics show. My feeling is this probably an intense but small scale rain shaft....possibly containing some small hail. The condition looks like a cold air aloft scenario by the looks of the clouds...pretty low topped and cold looking.

 

[samuel stone]

I saw a similar feature on a storm in northwest oklahoma on April 1st if this year, it was most definently a rain shaft and I would say yours was too. Stan R. may have seen this feature to as he was on this storm.

feature-

 

[David Drummond]

It's a rain or hail shaft, most definitely. Probably hail. It's getting pushed around be the winds a bit on the way down which given the visual lack of much storm organization is to be expected. I've seen stuff like this lots of times.

 

[Tom Mitchell]

I would say it was a cow. Two or three to be exact.

 

[David Wolfson]

It's important to note that the EXIF data for the photos shows that they're sequenced in reverse, from lower right (18:03:43) to upper left (18:08:37).

With this in mind, and looking at the lighting, dynamics, and relative motion of the features, it sure looks to me that the environment is entirely outflow and it's a heavy rain/hail shaft. There's no suggestion I can see of any tightened rotation anywhere that could possibly generate enough pressure drop to produce a condensation funnel in what doesn't look to be an extraordinarily humid environment. Thus the only other explanation for the visible feature is dust or precipitation. If dust, then you'd see it progressing upward; if precip, then downward. The motion is downward over the five minute period at a velocity consistent with precipitation.