Current Conditions
Publication: 2025-05-05
Snow MapSnow Water Equivalent
The map of the snow water equivalent can be found by clicking here.
- Warning: Please note that recent snowfalls or thaws that have caused an increase in snow cover or melting of part of the snow cover may not have been represented in the map. Therefore, the conditions shown on the map may not perfectly reflect current field conditions.
This map gives an overview, at the time of measurements, of the amount of water held in the snow cover compared to the amount of water it normally holds at this same time of year. The map covers the entire Ottawa River watershed. At a glance, it is possible to see if there was more or less snow than usual at a given time of the year.
It is important to note that the amount of water in the snow cover is only one of several factors that can influence the magnitude of the spring freshet. For more information on the factors that contribute to flooding, please consult our Frequently Asked Questions.
This map is provided in early February and March, and approximately every two weeks thereafter, until the major part of the snow cover is gone.
Reference
To reference this map, please use ‘Ministère de l’Environnement, de la Lutte contre les changements climatiques, de la Faune et des Parcs, 2025. Data from the Réseau de surveillance du climat du Québec, Direction de la surveillance de la qualité de l’air et du climat, Québec.’
Locations to display: River locations only | Reservoirs only | Other locations
Lake Coulonge at Fort-Coulonge
Current Conditions
(2025-05-05 15:00:00)
Current Conditions
(2025-05-05 15:00:00)
(2025-05-05 15:00:00)
Lake Deschenes at Britannia (Ottawa)
Current Conditions
(2025-05-05 12:00:00)
(2025-05-05 12:00:00)
Ottawa River at Chats Falls GS
Current Conditions
(2025-05-05 15:00:00)
(2025-05-05 15:00:00)
Current Conditions
(2025-05-05 15:00:00)
(2025-05-05 15:00:00)
Current Conditions
(2025-05-05 15:00:00)
(2025-05-05 15:00:00)
Ottawa River at Otto Holden GS
Current Conditions
(2025-05-05 15:00:00)
(2025-05-05 15:00:00)
River Levels and Flows
| Water levels at 24:00h in metres | 2025-04-28 | 2025-04-29 | 2025-04-30 | 2025-05-01 | 2025-05-02 | 2025-05-03 | 2025-05-04 | 2025-05-05 |
|---|---|---|---|---|---|---|---|---|
| Otto Holden Generating StationGraph View and Advanced Data Agency: OPG | 174.74 | 174.94 | 175.19 | 175.41 | 175.58 | 175.78 | 176.00 | 176.12 |
| MattawaGraph View and Advanced Data Agency: WSC | 153.64 | 154.03 | 154.01 | 154.01 | 154.18 | 154.36 | 154.37 | 154.32 |
| Des Joachims Generating StationGraph View and Advanced Data Agency: OPG | 149.95 | 150.17 | 150.32 | 150.48 | 150.61 | 150.80 | 150.91 | 150.97 |
| PembrokeGraph View and Advanced Data Agency: OPG | 112.77 | 112.83 | 112.82 | 112.85 | 112.87 | 112.84 | 112.87 | 112.87 |
| Lake Coulonge at Fort-CoulongeGraph View and Advanced Data Agency: HQ | 107.82 | 107.98 | 108.05 | 108.10 | 108.15 | 108.15 | 108.12 | 108.11 |
| Chenaux Generating StationGraph View and Advanced Data Agency: OPG | 86.03 | 85.87 | 85.84 | 85.78 | 85.82 | 85.74 | 85.68 | 85.70 |
| Chats Lake at ArnpriorGraph View and Advanced Data Agency: OPG | 75.07 | 75.17 | 75.19 | 75.26 | 75.26 | 75.27 | 75.26 | 75.24 |
| Lake Deschenes at Britannia (Ottawa)Graph View and Advanced Data Agency: WSC | 59.55 | 59.76 | 59.69 | 59.72 | 59.76 | 59.77 | 59.77 | 59.75 |
| Gatineau (Hull)Graph View and Advanced Data Agency: HQ | 43.10 | 43.30 | 43.37 | 43.42 | 43.49 | 43.52 | 43.53 | 43.54 |
| ThursoGraph View and Advanced Data Agency: HQ | 41.95 | 42.07 | 42.17 | 42.20 | 42.23 | 42.25 | 42.26 | 42.27 |
| GrenvilleGraph View and Advanced Data Agency: HQ | 41.50 | 41.65 | 41.66 | 41.66 | 41.71 | 41.71 | 41.70 | 41.68 |
| Carillon Generating StationGraph View and Advanced Data Agency: HQ | 40.51 | 40.51 | 40.49 | 40.49 | 40.50 | 40.50 | 40.50 | 40.48 |
| Average Daily Outflow (m3/s) | 2025-04-28 | 2025-04-29 | 2025-04-30 | 2025-05-01 | 2025-05-02 | 2025-05-03 | 2025-05-04 | 2025-05-05 |
|---|---|---|---|---|---|---|---|---|
| Ottawa River at TemiscamingGraph View and Advanced Data Agency: PSPC | 1817 | 1969 | 2118 | 2200 | 2249 | 2312 | 2400 | 2323 |
| Ottawa River at Otto Holden GSGraph View and Advanced Data Agency: OPG | 1873 | 2021 | 2149 | 2236 | 2298 | 2345 | 2419 | 2421 |
| Des JoachimsGraph View and Advanced Data Agency: OPG | 2412 | 2425 | 2599 | 2637 | 2662 | 2613 | 2749 | 2766 |
| Ottawa River at Chenaux GSGraph View and Advanced Data Agency: OPG | 2948 | 3191 | 3289 | 3354 | 3393 | 3452 | 3427 | 3431 |
| Ottawa River at Chats Falls GSGraph View and Advanced Data Agency: OPG | 3356 | 3586 | 3673 | 3746 | 3824 | 3826 | 3826 | 3777 |
| Lake Deschenes at Britannia (Ottawa)Graph View and Advanced Data Agency: WSC | 3278 | 3507 | 3673 | 3702 | 3819 | 3833 | 3845 | 3800 |
| Ottawa River at CarillonGraph View and Advanced Data Agency: HQ | 4815 | 5120 | 5494 | 5415 | 5482 | 5541 | 5563 | 5381 |
River Conditions Forecast
Spring runoff in the northern part of the basin remains very high. Reservoirs throughout the basin are being used to store runoff and reduce flooding as much as possible. Minor flood levels have been reached in most flood prone locations between Mattawa and Lake Deschenes. Levels may reach or exceed the major flood level in Mattawa and from Lake Coulonge down to Lake Deschenes depending on the amount and location of upcoming rainfall Tuesday and Wednesday. From Gatineau (Hull Marina) down to Hawkesbury / Grenville, levels are expected to exceed minor flood levels but should remain below major flood levels. Our website Forecasts section provides expected water levels over a four-day horizon in your area. Uncertain weather and hydrological factors play into estimating peak levels. On May 5, peak level estimates are: Mattawa (154.65 m), Pembroke (113 m), Lac Coulonge (108.3 m), Chats Lake (75.3 m), Lake Deschenes (59.95 m), Gatineau -Hull marina (43.8 m) and Thurso (42.40 m).
Additional content
About this map
This map includes markers representing the location of gauges where information on flows and water levels are available. Data collected at gauges shown on the ‘River locations only’ and ‘Reservoirs only’ maps is used for the integrated management of the principal reservoirs within the Ottawa River Basin.
Instruction:
The coloured markers on this map depict conditions (level or flow) as a range of conditions categorized in three groups: 
for normal conditions, 
for above normal, 
for below normal. The marker is 
when the current day’s value or percentile are not available. On the ‘River locations only’ map, the colour of the markers for locations with run-of-river facilities is based on flow conditions. On the ‘Reservoirs only’ map, the marker colour for all locations is based on the water level in the reservoir.
Click on any marker to see the most recent data from this location and what type of data is measured there. To view data related to the principal reservoirs in the basin, select ‘Reservoirs only’ in the upper right corner. Near real-time and historical data is available for additional locations by selecting ‘Graph View and Advanced Data’. Water levels at 24:00 means at midnight.
Terms of Use:
The data provided by this web service may not be reproduced or redistributed. Contact the Ottawa River Regulation Secretariat for information on how to obtain historical data directly from the data owner.
Users of the flow data, water level data, and hydrological forecasts shown on this website must recognize that such information is considered preliminary data. Users must therefore accept that the information provided carries an unspecified level of uncertainty and are advised to be cautious if they intend to use the information for decision-making. Please see the Disclaimer for further details.
The flow rates and actual levels can change rapidly without warning, particularly during the freshet period. We advise those using bodies of water to exercise caution and to always follow established safety guidelines when near water.
Understanding Range of Conditions:
The three ranges are based on percentiles, which are computed from the observations of the current day of the year over a period of 30 years (1991-2020). The percentile (P) is the percent of all data that is lower than the actual value for the current day of the year.
: Normal conditions, between P10% and P90%
: Above normal conditions, P is equal or greater than P90%
: Below normal conditions, P is lower than P10%
: Current day value or percentile not available