Otonabee Conservation has updated the Flood Warning for all watercourses/waterbodies in the Otonabee region watershed. This is a further update to the Flood Warning first issued on April 14, 2018.
A Flood Warning is issued when flooding is imminent or is occurring.
In both the Kawartha Lakes and Haliburton Lakes region, the forecast is for significant precipitation starting Tuesday/Wednesday (April 24/25) and continuing through Thursday. In total, this rainfall event is expected to bring 25 mm to 40 mm to the whole of the two regions before there is a return to partial sunshine on Friday (April 27). Then on Saturday (April 28) a smaller disturbance will again bring rain to the two regions. At the same time, air temperatures in both the Kawartha Lakes and Haliburton Lakes regions are forecast to be positive during both day and night with mostly double-digit highs.
Ouse River, Indian River an Tributaries of the Kawartha Lakes and the Otonabee River:
One week ago, snow fell across the Otonabee River, Indian River and Ouse River watersheds. This snow cover has now largely disappeared. With seasonal to above-seasonal air temperatures now hitting the area, the remaining snowpack is expected to disappear entirely in the coming few days.
Currently, the ground is saturated, and there remains significant pooling/ponding in low lying areas where there is poor drainage. This will worsen with the arrival of a significant rainfall event beginning Tuesday/Wednesday (April 24/25) that is expected to continue through Thursday (April 26).
In accordance with the snowmelt and rainfall, the water levels/flows in local rivers, streams, creeks and wetlands will increase. In addition, current minor/nuisance flooding will worsen, especially Tuesday/Wednesday/Thursday (April 24, 25 26) when 25 mm to 40 mm of rain is expected to fall on the Otonabee River, Indian River and Ouse River watersheds.
Kawartha Lakes, Otonabee River and Rice Lake:
The Snow water equivalent in the 4,367 square kilometer drainage area of the Halliburton Lakes region was recently measured to range from 40 mm to 90 mm. During the past week, below zero over-night air temperatures in the Haliburton Lakes region have kept that snowpack largely intact.
With both day-time and over-night positive air temperatures now arriving to the Haliburton Lakes region, inflows to the Kawartha Lakes from the north are, however, currently increasing due to the melting of the snowpack in the north.
When rain arrives starting Tuesday/Wednesday (April 24/25), the combination of rain on snow, warm air temperatures and frozen ground conditions will cause a significant increase to the inflows to the Kawartha Lakes causing the Kawartha Lakes to rise. As a result, the outflow from the Kawartha Lakes through the Otonabee River, will also increase, which in turn, will increase Rice Lake water levels.
Throughout the coming days, Otonabee Conservation will continue its monitoring of current conditions and forecasts.
This Flood Warning will next be updated no later than 3:00 p.m., Tuesday, April 24, 2018.