Higher streamflow, but low risk
As the community watches the Oldman River rise this week, we wanted to give some context around streamflow in and around Lethbridge.
Oldman River Streamflow
The river is under a high streamflow advisory, but that’s not as scary as it might sound. As of 9:30 a.m. Tuesday, the streamflow was approximately 615 cubic metres per second (m3/s). Provincial forecasting shows the river peaking on Wednesday evening, between 750 m3/s and 1,000 m3/s. That’s higher than we’ve seen in a few years, but well below the threshold for overland flooding.
The forecasted peak may bring minor flooding to low-lying river valley parks and trails. Crews are monitoring the situation and will proactively close impacted areas. Residents are asked to avoid the river valley trails at this time for their safety and to protect the trails from any additional damage. Soft ground and high winds also pose a risk of downed trees. Please report any downed trees in public spaces to Lethbridge 311.
The province provides an online flood mapping tool. It shows which areas of the city would be impacted at various flow rates. Access the tool by clicking the ‘Inundation’ tab at https://floods.alberta.ca/. This webpage also offers information on current forecasts, hazards and flood likelihood maps.
River Safety
Lethbridge Fire and Emergency Services (LFES) is advising the community to stay away from the Oldman River and riverbanks.
“High water levels and fast-moving flows can create dangerous conditions with little warning,” says Charles Schoening, Water Rescue Team Lead, Lethbridge Fire & Emergency Services. “Riverbanks may be unstable; trails and access points may be slippery and debris in the water can create serious hazards.”
Residents are asked to avoid walking, playing, floating, kayaking, boating, paddleboarding or swimming in or near the river until conditions improve.
LFES reminds residents to:
- Stay away from the river and riverbanks
- Keep children and pets well back from the water
- Watch for unstable banks, slippery trails and fast-moving water
- Obey all posted signs, barriers and closures
- Never drive, walk or bike through flooded areas
- Call 9-1-1 if someone is in immediate danger
Boating advisory in effect
The Oldman River now exceeds recommended safe flow rates for boating or swimming. LFES has issued a boating advisory, effective immediately. For the safety of river users and emergency responders, LFES advises everyone to stay off the Oldman River and St. Mary River until conditions return to safer flow rates and the boating advisory is lifted.
Road Safety
The City’s Transportation team is monitoring roads for any flooding caused by standing water from the heavy rain. Residents are asked to drive with caution and lower their speeds to avoid the risk of hydroplaning. Please report any flooded roads to 311.
Water Treatment
The City’s Water Treatment Plant continues to deal with murky water. Crews are monitoring conditions and responding as necessary.
“Our tap water remains safe to drink,” says Jason Drenth, General Manager of Water & Wastewater and Electric Utility. “We ask the community and our regional customers to continue voluntary conservation efforts. This protects our equipment and maintains safe treatment standards.”
Local storm ponds are also much higher than normal. This includes some surrounding pathways being submerged. Residents are asked to remain a safe distance from the ponds and obey all closures signs.
As conditions change, the City will provide timely updates to ensure residents stay safe and well‑prepared.
For Public Inquiries:
Call or chat 311 | Monday to Friday, 8 a.m. to 4:30 p.m.