Amazing winter convection - graupel, snow, and quarter-sized hail, Pagosa Springs, CO
This evening in and around Pagosa Springs, CO, I observed some of the amazing winter convection I have ever seen - it produced a little snow, a lot of graupel, and dime to quarter-sized hail. The temperature while this was going on was mostly in the upper 30s to low 40s, although when the precipitation in the second cell I observed changed from mostly graupel to mostly snow, it quickly dropped to around 34.
I knew I wasn't dealing with ordinary winter snow showers when, walking out the door of a restaurant where my wife and I had just finished dinner after my last ski day of the season, I saw this:
This picture was taken near the east edge of Pagosa Springs, looking northwest at the updraft base of the southeastward-moving cell. Note the knuckled anvil! This was about 100 feet from where I would later photograph quarter-sized hail. Shortly after this picture was taken, a little small graupel began to fall, mixed with a few wet snowflakes and maybe a few raindrops.
I moved another mile east to get into the core and see what was falling. Lots of graupel and eventually a little dime-sized hail:
Returning to the east edge of town, I found this:
While I would certainly classify this as hail, it really seemed to be a sort of hail-graupel hyprid - probably formed mostly by dry accumulation (i.e. rime accumulating on what started out as a snowflake), but it did seem to have gone through some melt-freeze cycle, i.e. the "wet accumulation" process that produces hail with storms that occur in spring and summer environments. But this cell had almost no rain; mostly graupel and a little snow. No thunder and lightning that I saw, either. After this passed I noticed another even stronger-looking cell to the west, and moved to intercept it. It produced even more copious amounts of quarter-inch graupel, which then turned to snow. By now it was dark, so I called it a day, but on the way back noticed yet another cell moving on a similar track to the first one, and this one produced quite a bit of thunder and lightning, in contrast to the first two which produced none that I saw.
I've always wondered whether it is really possible to get snow and hail in the same storm - thought I saw it once a couple years ago between Santa Fe and Albuquerque, but now I know it's definitely possible. Severe hail, even, as the picture above shows.
I do have some video which eventually I will get posted, but it may be a while as I have a lot of competing commitments.
Last edited by John Farley; 04-17-2012 at 11:21 PM.
Pagosa Springs, CO
We were watching this stuff last night at work. Got a few reports of dime sized hail near GJT and Silt as well. Thanks for posting this. dp
Full report with discussion, additional pictures, and video is now available at:
Pagosa Springs, CO