Topic: Hail drifts

[Jimmy Deguara]

Jimmy,

what are haildrifts and what conditions cause them - i've heard of snow-drifts, but not hail drifts before.

Big Pete
(a learning scholar)

And cloudfairy said:

The pictures look like wet snow to me....
Haven't heard of hail drift either.

It's definitely hail! Yes it does look like snow and often get's misreported as such. Take a closer look at some of the images and you will see individual stones on the road.

'Hail drifts' perhaps a slang term or jargon from storm chasers refers to hail coverage. In this case, due to perhaps piling of snow in a specific region within corridors piles to about 10 to 15cm in depth. Hail drifts of up to 1 metres or more have been reported in some slow moving storms particularly HP supercells where almost pure hail has continually fallen.

Regards,

Jimmy Deguara

[Jimmy Deguara]

With hail drifts...

There will always be some piling up of hail particularly when hailstones are smaller and can float down though it still requires a torrent of hailstones. Not as common with the larger hail events ie golf balls however. But then again, such hail size density requires a near hail dump (the whole storm virtually dies rather rapidly dumping its load) or a specifically incredible hail production environment whereby virtually all precipitation falls as hailstones.

I have hinted above to an extraodinary event in Canada severeal years ago where a metre of hail was dumped by a stationary or very slow moving storm - I think it was a supercell. David and I observed a storm in early May in extreme south eastern Nebraska that also became stationary after slowing down and then began to move in reverse before getting swallowed by a fast moving squall line from the west!

Regards,

Jimmy Deguara

[David C]

Andrej,
 David and I observed a storm in early May in extreme south eastern Nebraska that also became stationary after slowing down and then began to move in reverse before getting swallowed by a fast moving squall line from the west!

Regards,

Jimmy Deguara

I think that was extreme SE South Dakota Jimmy, when we bumped into Bobby Eddins. That storm was producing up to baseball sized hail  -- it would have been quite extraordinary to have been under such a prolonged dump of large to even giant hailstones. I will see if I have the timelapse tape and will post a link to it on the weekend. 

We had three pretty spectacular hail drifts that I can recall in the 80s at Padstow. One in 1980, while I was young at the time, left a lasting impression with the hail having piled up to a depth of 30cm or more in places, and it occurred during the early morning. The one in 86, was notable in that the drifts were composed of hail to golfball size, and large enough to break some of our windows at home. Good times

[Jimmy Deguara]

David,

I can't believe I wrote Nebraska when I was thinking South Dakota - goes to show what happens when in a hurry! Yes the storm was nice to watch - steep lapse rates and clean updrafts that eventually broke the cap. Even a tornado warning was issued for the storm.

Regards,

Jimmy Deguara

[Michael Bath]

There are a few examples of hail drifts in our hailstones gallery - have a browse starting here:

http://australiasevereweather.com/photography/hailstones.html

10th Oct 2008 by Jimmy NE of Mudgee stands out as a recent example.
http://australiasevereweather.com/photography/hailstones/hail_stones0337.html

MB