It’s exactly the forecast we didn’t want heading into the weekend. For the third time in April, a Colorado low is targeting the region with yet another round of significant rainfall.
“We need to be on guard this weekend for overland flooding, and rapid rises in creeks and streams,” said CMOS Accredited Weathercaster Chris Sumner. “The ground is saturated, and in many areas is still relatively frozen. It simply doesn’t have the capacity to absorb any additional moisture.”
Environment Canada has issued rainfall warnings for the Red River Valley and all of Southeastern Manitoba including the City of Winnipeg. Many other communities that have been hit hard by the last two storms and are already dealing with some flooding are also under the warning, including Morden, Carman, Winkler, Altona, Emerson, Morris, Vita and Steinbach areas.
Another 20-50 mm of rain will begin Friday night as the third major low pressure system in as many weeks drops even more rain on the region.
“Over the last couple of days areas most impacted last weekend started to see water levels drop, which is a positive because at least there will be some capacity in municipal and provincial drain systems to take on more run-off,” explained Sumner. “With that said, many drains are still running high, and significantly damaged rural roads will only take a further beating from this third round of precipitation.”
According to Environment Canada, the rain will lift northwards into the province Friday night, bringing 20 to 50 mm over the following 24 to 36 hours. Like the previous storm, embedded thunderstorms are also possible, and could bring high rainfall rates to the region.
“Throughout the week the forecast models have shown a slow inching eastward of this system, and that has put us in the position of facing, perhaps, not as much rain as last weekend, but potentially still a considerable amount,” he added. “If there is one positive to take away at this point, it appears the heaviest rainfall may stay south of the border, but if it falls in the Red River or Pembina basins in North Dakota, all that water will still ultimately make its way to and through Manitoba.”
Sumner noted current guidance is the bulk of the rain will fall Friday night overnight into Saturday and then throughout the day. Sunday is trending toward on again, off again shower activity.
“If you haven’t had the opportunity to prepare for potential overland flooding, I strongly encourage you to do that Friday before the rain starts,” he stressed. “A number of scenarios this week have shown us how quickly overland flooding can arrive and increase in severity, so putting those plans in place now may prove valuable later.”