Forecast for 2026-04-25

River conditions forecasts posted on 2026-04-25 by Ottawa River Regulating Committee

Water levels and flows along the main stem of the Ottawa River are rising gradually from Mattawa to Pembroke and are stable or slightly declining between Lake Coulonge and Carillon. In Mattawa, water levels have exceeded the minor flood level yesterday and could reach major flood level over the next few days. With accelerated snowmelt expected in the northern part of the watershed, northern reservoirs are now passing increased flows downstream. Water levels and flows are expected to continue increasing gradually from Mattawa to Pembroke and to be fairly stable in downstream locations over the next few days. Our website Forecasts section provides expected water levels over a four-day horizon in several areas. The rate of snowmelt in the northern portion of the basin and the potential for rainfall over the coming weeks remain uncertain. As a result, in the coming weeks, a second flood peak remains possible from Pembroke to the Montreal region, as well as the possibility of levels at Mattawa exceeeding major flood levels for the first time. A rapid melt combined with rainfall could lead to water levels higher than those observed between April 19 and 22 in all locations.