Forecast for 2026-04-24

River conditions forecasts posted on 2026-04-24 by Ottawa River Regulating Committee

Water levels and flows along the main stem of the Ottawa River are stable or slightly declining between Pembroke and Carillon, while continuing to rise gradually in Mattawa. Water levels are expected to exceed the minor flood level in Mattawa today (Friday). With accelerated snowmelt expected in the northern part of the watershed, northern reservoirs are now passing increased flows downstream. This may lead to increasing water levels in Pembroke and stable or slowly decreasing levels between Lake Coulonge and Carillon. 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.