The snow is practically constant so it shouldn't be thermal or autofocus related. Autofocus does not seam to hunt, it actually has tons of depth of field.

I think it's a combination of OIS, rolling shutter and high frame rate. OIS is IMHO not fast enough and some of the frames catch OIS in motion which makes the rolling shutter problem appear. Same as shaking the camera vertically without OIS. Just a theory:)

If we're having a straw poll on this, my vote is that its a thermal effect - you can see rails that must lead to a door, where quite probably one would expect to find an overhead heater bellowing a heat curtain (as found in many public buildings in cold lattitudes).

Colin, you mention you were outside, perhaps the door nearby was opened during the shot? Can you recall any nearby heat sources other than yourself - or maybe you removed gloves exposing toasty hands ...? ;0)

It's definitely something that deserves some more testing!

It's isolated and looks thermal to me.

A good way to test the rolling shutter theory would be to setup a CCD camera alongside shooting at 60fps (eg, an HD250) to see if the same effect is present.

Colin, do you have access to any other CCD cameras on campus that you could do a quick comparison with?

I'm not following anyone who thinks this is a rolling shutter artifact, please explain.

I've shot rain, moving water, why would snow be any different.

This isn't the first time I've (and many) have seen this type of thermal wave distortion.

Isolated being the key word here. It can't be rolling shutter because of this very fact.
It sure as hell looks like a thermal to me.