Thunder Lake dam
Thunder Lake
Nestled in the heart of Cass, Minnesota, Thunder Lake is a captivating water resource that offers a plethora of recreational opportunities for enthusiasts of all ages. This concrete dam, completed in 1934, stands at a height of 18 feet and boasts a normal storage capacity of 7750 acre-feet, providing ample space for water-based activities such as fishing, boating, and swimming. With a surface area of 1347 acres and a drainage area of 16.8 square miles, Thunder Lake is a picturesque destination for those seeking to immerse themselves in the beauty of Minnesota's natural landscape.
Managed by the Minnesota Department of Natural Resources, Thunder Lake is regulated, inspected, and enforced to ensure the safety and sustainability of its water resources. The dam's hazard potential is considered low, with a satisfactory condition assessment as of April 2015. While the dam's primary purpose is recreation, it also serves as a vital component of the local ecosystem, providing habitat for a variety of wildlife and contributing to the overall health of the Willow River-TR watershed. Visitors to Thunder Lake can enjoy its tranquil waters, scenic surroundings, and abundant recreational opportunities while appreciating the importance of responsible water resource management in the face of climate change.
As climate change continues to impact water resources and ecosystems worldwide, Thunder Lake stands as a testament to the importance of sustainable water management practices. With its state-regulated status, satisfactory condition assessment, and low hazard potential, Thunder Lake serves as a model for other recreational water bodies in Minnesota and beyond. Whether you're a climate enthusiast, water resource advocate, or simply a nature lover looking for a serene escape, Thunder Lake offers a unique opportunity to appreciate the beauty and resilience of our natural world in the face of environmental challenges.
Dam data reference
Condition Assessment
- Satisfactory
- No existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
- Fair
- No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action.
- Poor
- A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency.
- Unsatisfactory
- A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
- Not Rated
- The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.
Hazard Potential Classification
- High
- Dams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
- Significant
- Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environmental damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
- Low
- Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
- Undetermined
- Dams for which a downstream hazard potential has not been designated or is not provided.
Plan around the weather
Same NOAA / yr.no feed Snoflo's iOS app uses. Watch the precipitation column on the meteogram -- rain on the basin upstream typically lifts inflow 24-72 hours later.
Next 5 days, hour by hour
Temperature line with weather symbols on top, snow + rain accumulation as columns, humidity as a dotted line.
5-day forecast table
Every 3 hours, broken out across temperature, snow, rain, humidity, and wind. Each cell is colour-coded relative to the column min/max.
| Time | Condition | Temp (°F) | Snow (in) | Rain (in) | Humidity (%) | Wind (mps) | Wind dir |
|---|---|---|---|---|---|---|---|
| Loading detailed forecast… | |||||||
15-day temperature & precipitation
Daily temperatures, snow, and rain projected over the next two weeks.
Nearby streamflow gauges
USGS streamgauges around Thunder Lake -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Mississippi River At Grand Rapids | 457 cfs | → |
| Mississippi River At Aitkin | 1,750 cfs | → |
| Prairie River Near Taconite | 160 cfs | → |
| Mississippi River At Brainerd | 2,040 cfs | → |
| Crow Wing River At Nimrod | 343 cfs | → |
| Crow Wing River Near Pillager | 1,220 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Thunder Lake.
Boat launches
Campgrounds
- Land O'Lakes Sf - Baker And White Oak Lake
- Washburn Lake - Land Olakes State Forest
- Land O'Lakes Sf - Clint Converse
- Clint Converse - Land Olakes State Forest
- Mabel Lake
- Mabel Lake -Usfs
Fishing spots
Paddle runs
- The Discharge Of The Flood Diversion Channel To Riverton
- The Confluence Of The Prairie River To The Boundary Of Logan And Workman Townships
- The Boundary Between Logan And Workman Townships In Aitkin County To The Dam Entrance Of The Flood Diversion Channel
- Lake Winnigigoshish To Blackwater Lake
- Cass Lake To Lake Winnibigoshish
- The 25-Acre Island Just South Of Brainerd To Roscoe Island
Track Thunder Lake in the Snoflo app
Save this dam as a favorite and get the local NOAA / yr.no forecast plus regional flow context wherever you are.
About Thunder Lake
Where does the data for Thunder Lake come from?
Structural and regulatory data come from the U.S. Army Corps of Engineers' National Inventory of Dams (NID). Weather forecast comes from NOAA / yr.no -- the same feed Snoflo's iOS app uses.
How often is the report updated?
NID structural data refreshes annually as the Corps publishes updated assessments. The weather forecast refreshes throughout the day.
What does the Low hazard rating mean?
The Corps of Engineers' hazard potential classification grades probable consequences if the dam fails: High = probable loss of human life; Significant = no probable loss of human life but possible economic loss / environmental damage; Low = no probable loss of human life, only minor economic / environmental losses. See the Dam Data Reference card above for the full definitions.
What's "% of normal"?
The current storage value compared to the historical average storage on this calendar day. 100% = right on average; values above 100% mean above-normal storage (wet year); values below mean below-normal (dry year or drought).
Can I get alerts when storage crosses a threshold?
Yes -- alerts are managed in the Snoflo iOS app. Favorite this dam, set a threshold, and you'll get a push the moment conditions cross.
Other water bodies near here
Snoflo-tracked reservoirs and dams within driving distance of Thunder Lake.