Thunder Lake vs Washburn Lake
Water quality, depth, fish species, and recreation comparison.
Thunder Lake has a higher water quality grade (A, Excellent) than Washburn Lake (A, Excellent). Both are in Cass County, Minnesota.
Thunder Lake and Washburn Lake are both in Minnesota — a same-state head-to-head where the comparison comes down to lake-specific differences in depth, watershed, and monitoring history rather than the broader state-level water-quality regime. The grades are close: Thunder Lake (A) and Washburn Lake (A) are within one letter of each other on the LakeGrade rubric. The per-parameter sub-grades below will show where the small differences actually live.
With grades this close, the choice between the two lakes turns on non-water-quality factors: depth, fish species, public access, distance from home. The per-lake pages below cover all of those.
Thunder Lake
Crystal clear, you can see 16.4 ft down.
Washburn Lake
Good clarity, visible to about 14 ft.
Side-by-Side Metrics
| Metric | Thunder Lake | Washburn Lake |
|---|---|---|
| Overall Grade | A (Excellent) | A (Excellent) |
| Water Clarity | 16.4 ft | 14 ft |
| Phosphorus | 10 µg/L | 11 µg/L |
| Chlorophyll-a (Algae) | No data | No data |
| Maximum Depth | - | - |
| Surface Area | 1.3K acres | 1.6K acres |
| Public Access | Unknown | Unknown |
| Fish Species | 1 | 1 |
| Trophic State | oligotrophic | oligotrophic |
Bold value = better for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better).
Verdict
Thunder Lake wins on overall water quality with a Grade A versus Washburn Lake's Grade A. Water clarity: 16.4 ft vs 14 ft. For fishing diversity, Thunder Lake also leads with 1 species.