Flash Lake
Flash Lake in Lake County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 9 ft visibility. Maximum depth: 24 ft. Surface area: 82.77 acres.
- Clarity
- 9 ft
- Max depth
- 24 ft
- Area
- 83 acres
- Trend
- ↑ Improving
- Public access
- No
Next lake in Lake County
Why Flash Lake has no grade
We grade a lake only when its monitoring record clears the evidence bar: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Flash Lake, the only measurement available is water clarity, which is not a water-quality indicator on its own — EPA's National Lakes Assessment does not grade clarity. Sampling here has recorded water clarity, but not phosphorus and algae (chlorophyll-a).
Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.
Sampling is run by MPCA and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Flash Lake is a 83-acre lake in Lake County, Minnesota with a maximum depth of 24 feet. Overall water quality is improving over recent sampling years. The lake supports 5 documented fish species including green sunfish, northern pike, and walleye. No public access — the lake is private or restricted.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2020-07-24. Grade methodology: LakeGrade methodology.
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Swimming Safety
Not ratedLimited data
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Flash Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Moderate clarity, visible to about 9 ft. Trophic State Index: 45.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 9 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 45 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Flash Lake
Compare lakeside cabins, hotels, and vacation rentals near Flash Lake in Lake County, Minnesota — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water.
Top-rated places to stay near Flash Lake
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Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 24 ft |
| Surface Area | 83 acres |
| Shoreline Length | 3 mi |
| Littoral Zone | 71% |
| Public Access | No |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Flash Lake
DNR Fisheries Survey Summary
7 surveys on file from MN DNR Fisheries. Most recent: 2024-06-17 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Walleye | 19.41 | 1.42 lb |
| Yellow Perch | 17.73 | 0.11 lb |
| Northern Pike | 7.11 | 2.3 lb |
| White Sucker | 0.67 | 2.81 lb |
| Green Sunfish | 0.33 | 0.06 lb |
CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE = more abundant in standardized sampling.
Length Distributions
Number of fish caught at each inch class in the most recent survey that recorded lengths. Red dashed line marks an approximate trophy threshold for that species.
Walleye
Yellow Perch
Northern Pike
White Sucker
From the 2024-06-17 survey
Flash is an 83-acre lake located 18 miles northeast of Ely in the Superior National Forest. It is comparable to Erickson, Hatchet, and Oriniak lakes in the Tower area. The lake is clear, moderately productive, and has a maximum depth of 24 feet. The surrounding forest is regenerating from a severe windstorm and…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Flash Lake. 1 report on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — FlashFisheries Lake Survey · MN DNR LakeFinder
Water Quality Trend: ↑ Improving
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.221 m/yr | 5 |
EPA Impairment Status
Flash Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN38-0630-00 · Official waterbody report
Graded lakes near Flash Lake
Flash Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Lake County
Frequently asked questions about Flash Lake
What is the water quality grade for Flash Lake?
- Flash Lake in Lake County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 9 ft visibility. Maximum depth: 24 ft. Surface area: 82.77 acres.
Is Flash Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Flash Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
How deep is Flash Lake?
- Flash Lake has a maximum depth of 24 feet. The lake covers 82.77 acres.
What fish are in Flash Lake?
- Fish species found in Flash Lake include green sunfish, northern pike, walleye, white sucker, yellow perch. Flash Lake is located in Lake County, Minnesota.
Explore Flash Lake across LakeGrade
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Where this data comes from
4 measurements from 2 monitoring stations, 2020. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA4 samples · 2020
Analytical methods
- Field measurement/observation, generic method
Monitoring station identifiers (2)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder