Ice causing overland flooding in much of southern Manitoba

Manitoba Flood Bulletin No. 4

Province of Manitoba – Manitoba Infrastructure’s Hydrologic Forecast Centre reports overland flooding is occurring across much of southern Manitoba due to ice in the drainage network. Ice jamming is also occurring on some major rivers and smaller tributaries.

Partial ring dike closures are underway or completed at Gretna, St. Adolphe and Brunhild. PTH 75 is projected to remain open. As a precautionary move, to maintain travel on PTH 75 through Morris, the province will construct a ramp at the north end of the town near the Morris river. This has been done in past floods to keep traffic moving.

High water advisories are in effect for Overflowing, Valley and Vermillion rivers.

Flood watches are in effect for Turtle, Woody, Swan, Whitemud, and Red Deer rivers.

Flood warnings are in effect for Fisher, Morris and Pembina rivers as well as Pipestone Creek.

The Red River Floodway began operation Friday morning. Flow in the floodway channel is 11,654 cubic feet per second (cfs) (330 cubic metres per second [cms]). Flow at James Avenue this morning was 57,845 cfs (1,638 cms).

The water level at James Avenue in Winnipeg increased 1.2 feet overnight to 19.4 feet. This rise was due to an upstream ice run that created a surge of flows downstream. With the floodway in operation, water levels at James Avenue could decline to 19.0 feet on Sunday. The timing of the ice run on the Assiniboine River could result in a minor increase in water levels at James Ave.

The Portage Diversion began operation on Friday morning. It is being operated to limit flows on the lower Assiniboine River to minimize ice jamming. Flow in the channel is 3,132 cfs (89 cms) and flow on the lower Assiniboine River is 5,170 cfs (146 cms).

Ice is still in place on many rivers and tributaries which is affecting gauge readings. The risk of ice jamming in drains and small tributaries is present as flows start to rise. Ice jamming is developing on southern Manitoba’s major rivers and smaller tributaries.

Weather

Temperatures across southern Manitoba are above average and warm temperatures this week are expected to continue melting and run-off. Trace precipitation was recorded in southwestern Manitoba in the last 24 hours.

Snowpack and run-off

Much of the snow has already melted in southern Manitoba with the majority of the snow remaining in wooded areas.

A portion of the snowpack remains in the western part of the Souris River Basin, the Parkland Region, the Duck Mountain area, the Riding Mountain area and northern Manitoba.

A combination of rapid melt, ice jamming and blocked culverts may lead to a rapid rise in water levels on tributaries and may cause localized overland flooding. Municipal and provincial crews are actively thawing culverts on a priority basis.

Since run-off may occur quickly, landowners who normally store a portion of run-off in dugouts for irrigation or other water retention structures are encouraged to retain water.

Red River Basin

The Red River and its tributaries are rising rapidly. Significant increases continue on the Morris and La Salle rivers.  Pumping continues within the Red River ring dike communities.

Ice remains in the main channel of the Red River and is flowing through all upstream locations including, Emerson, Letellier and St. Adolphe.

The Red River upstream of the floodway inlet is currently at 756.9 ft. and is expected to crest on April 4-5 at a level of 760.5 to 761.5 ft. The forecast is being assessed on an ongoing basis and updates will be provided regularly.

Pembina River Basin

Water levels and flows on the Pembina River are stabilizing as ice jamming is subsiding.

Overflows from the Pembina River in the U.S. are impacting Gretna. A partial dike closure was completed in Gretna at the border. Flows overtopped the border road yesterday evening but have since receded.

Assiniboine River Basin

Major tributaries of the Assiniboine River are still increasing.

The Shellmouth Reservoir has been drawn down in preparation for spring run-off. The water level is at 1387.1 ft. Outflows from the Shellmouth Dam are being matched to inflows to preserve reservoir storage for the expected peak inflows. Inflows to the reservoir are approximately 3,559 cfs (101 cms). Outflows were increased to 2,019 cfs (57 cms) on Friday evening.

The Shellmouth Reservoir Regulation Liaison Committee will meet Monday to discuss operating plans. Outflows from the Shellmouth Dam may be increased to 3,000 cfs (85 cms) depending on downstream ice conditions. Ice remains in place on the upper Assiniboine River.

Ice is still in place on the lower Assiniboine between Portage la Prairie and Headingley.

Souris River

Flows on the main stem of the Souris River have not significantly reacted to the run-off from the melt. Tributaries of the Souris River are increasing.

Flows on the Pipestone Creek are continuing to increase and are currently recorded at 855 cfs (24 cms), this flow may be ice affected and will be monitored. The ice jam that occurred at Cromer has been cleared.

Interlake Region

The Fairford Water Control Structure is being operated for maximum possible discharge and outflow from Lake Manitoba is approximately 7,921 cfs (224 cms). Lake Manitoba water levels are recorded at 812.4 ft. Flows into Lake Manitoba through the Waterhen River are 5,569 cfs (158 cms).

Fisher River flows have declined at East Branch and Fisherton. Flows at Dallas have crested. There could be surges due to releasing ice jams upstream. Overland flooding has been reported on the Peguis River First Nation.

Flows on the Icelandic River are decreasing.

Manitoba’s major lakes are at above average water levels for this time of year and all lakes are still ice covered at this time.

Parkland Region

Tributaries in the southern Parkland are beginning to respond to run-off. Run-off rates will increase due to warming temperatures. Ice is beginning to move on the rivers and ice jamming remains a concern.

The Pas and Northern Manitoba

Run-off has begun in the Red Deer River watershed. Snowmelt and resultant run-off has been minimal in watersheds further north.

Flood Information

People are reminded to be watchful of local waterways, as flood conditions can develop quickly.

Avoid driving through moving water as the water depth can be unpredictable and current can push vehicles off the road.

People are reminded that ditches and culverts contain fast moving water which could be hazardous and should be avoided.

It is strongly advised that people be careful if venturing out onto what may appear to be frozen rivers and lakes, due to potential weak ice conditions.

Since run-off may occur quickly, landowners who normally store a portion of run-off in dugouts for irrigation or other water retention structures are encouraged to retain water.

Homeowners should check their sump pumps and hoses to ensure they are fully functional.

Up-to-date flood information can be found at on the Province of Manitoba website or on Twitter at www.twitter.com/MBGov.

For current highway conditions, call 511, visit www.manitoba511.ca, or follow the Twitter account at www.twitter.com/MBGovRoads for closures. A Manitoba 511 app is now available for download at http://residents.gov.mb.ca/apps/511.html.

About the author

Comments

explore

Stories from our other publications