Wednesday, December 14, 2011

Freezing drizzle leaves icy conditions in Winnipeg/southern MB...

Freezing drizzle was observed across Winnipeg and much of southern MB today as a moist mild airmass brought extensive low cloud and misty conditions across a large part of the Northern plains and eastern Prairies. The image here is what the Bishop Grandin webcam looked like this evening in the south part of Winnipeg, a result of a coating of freezing drizzle on the webcam lens. Kind of pretty actually.. looks like an impressionist oil painting! Freezing drizzle can sometimes occur in moist stagnant airmasses in the winter when temperatures are close to but below freezing, although it's not as serious as freezing rain which can lead to greater ice accumulations in a shorter time. However, an extended period of freezing drizzle can leave a thin coating of ice on exposed surfaces, with slippery conditions on untreated roads and walkways. Drier and colder conditions are expected overnight into Thursday as brisk northwest winds usher in a colder airmass from the north. Temperatures will return to normal over the next couple of days before another warmup this weekend. Some light flurries are possible from time to time, but overall no significant snowfall is expected over the next week as the snow drought continues over southern MB.

4 comments:

  1. Rob....
    If you could please tell me .....what are the chances of Winnipeg area and the Red River Valley ever getting a major ice storm??? I'm talking about ice accumulations of a inch or more so that power lines are sagging and tree limbs are snapping??

    Could the ice storm of 1998 in eastern Canada in theory ever happen in this area???

    ReplyDelete
  2. daniel..

    Yes, ice storms can and have occurred in the RRV and southern MB, although they are far less common than in eastern Canada. Back in March of 1983? (I think), there was a disastrous ice storm over western MB and ND that took down several radio and TV transmission towers, and knocked out power to thousands with ice up to 4" thick recorded on power lines. The most likely scenario for a major ice storm is a Colorado low type system coming up from the Dakotas in late winter/early spring (esp March or April) pushing in a lot of warm moist air from the south as rain, with cold northeast winds over southern MB maintaining below freezing temperatures at the surface. This is the classic setup for freezing rain. In order to get the large amounts of freezing rain that would cause serious damage, you need pcpn duration and intensity.. so the freezing rain setup needs to last a long time (on the order of 12 hours or more) and fall heavy at times (accumulating to 25 mm or more) Thus the system would have to be slow moving, or would have to a have a couple waves of pcpn that would affect the same area for maximum accumulations.

    It's rare, but it's certainly possible, and I'm surprised that we haven't seen a repeat of the 1983 ice storm here since then. Back in February 2009, we had about 15 mm of freezing rain in Winnipeg that turned roads to skating rinks (literally!) but even that was fairly tame compared to what a more serious freezing rain storm could do. I think it's only a matter of time before southern MB sees another ice storm that rivals 1983.

    ReplyDelete
  3. Here is a good poll question!
    for ROB to make:

    Will Winnipeg have at least 1 inch snow cover ( white Christmas) on December 25???

    ReplyDelete
  4. There is an article on WDAZ news that according to one individual says that ND could have one of the coldest winters in decades, maybe even 40 years......LOL

    It would be very tough to get much colder than the 1995- 1996 or 1996-1997 winter and the rate we are going now!!!!......LOL

    ReplyDelete