Expansive Soil in Wyoming: County Ratings
1 of the 21 rated counties in Wyoming have a dominant shrink-swell rating of High or Very High. Each rating below is the NRCS shrink-swell class covering the largest share of the county's mapped soil acres, computed from USDA SSURGO data. Open a county for the full class breakdown and what it means for a slab foundation.
| County | Dominant class | High + Very High share | Survey coverage |
|---|---|---|---|
| Albany County | Moderate | 4% | 99% |
| Big Horn County | Low | 22% | 97% |
| Campbell County | Moderate | 24% | 96% |
| Carbon County | Low | 0% | 22% * |
| Converse County | Moderate | 12% | 99% |
| Crook County | High | 54% | 98% |
| Fremont County | Moderate | 8% | 97% |
| Goshen County | Low | 2% | 96% |
| Johnson County | Low | 24% | 95% |
| Laramie County | Low | 7% | 100% |
| Lincoln County | Low | 14% | 65% * |
| Natrona County | Moderate | 21% | 98% |
| Niobrara County | Low | 13% | 96% |
| Park County | Low | 0% | 56% * |
| Platte County | Low | 0% | 99% |
| Sheridan County | Moderate | 23% | 100% |
| Sweetwater County | Low | 3% | 99% |
| Teton County | Low | 6% | 92% |
| Uinta County | Low | 6% | 100% |
| Washakie County | Moderate | 5% | 100% |
| Weston County | Low | 31% | 99% |
* Less than 80% of this county's map acres have completed soil survey data; treat its rating as provisional.
How these ratings are computed
Ratings come from USDA NRCS SSURGO soil survey data: for each soil component we take the maximum linear extensibility percent (lep_r) in the top 100 cm, apply the NRCS Handbook Part 618 class limits (Low under 3 percent, Moderate 3 to 6, High 6 to 9, Very High 9 and above), assign map units by plurality of component percent, and roll acres up to the county. Full details on the methodology section of the lookup page. A county rating is not a parcel-level geotechnical assessment.