Forecast for 2026-04-23

River conditions forecasts posted on 2026-04-23 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. Minor flood levels in Mattawa could be exceeded starting early tomorrow (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, a second flood peak remains possible in the coming weeks from Mattawa to the Montreal region. A rapid melt combined with rainfall could lead to water levels higher than those observed between April 19 and 22 in all locations.