Hanna dam
Hanna
Hanna is a concrete dam located in Carbon, Wyoming, along the Rattlesnake Creek, with a primary purpose of water supply. Built in 1934 by designer Ellis Hudman, this dam stands at a height of 25 feet and has a hydraulic height of 21 feet, providing a normal storage capacity of 62 acre-feet. With a fair condition assessment as of July 2017, Hanna has a low hazard potential but a high risk assessment rating of 2, indicating the need for ongoing monitoring and management.
Owned by the local government, Hanna is regulated by the Wyoming State Engineer's Office, with state permitting, inspection, and enforcement in place. The dam features a spillway width of 12 feet and three valve outlet gates for operational control. While no associated structures exist, Hanna serves as a crucial water resource infrastructure for the surrounding area. With a risk management plan in place, Hanna continues to play a vital role in water management and supply within the region.
Despite its age, Hanna remains a key structure in the water resource management system, demonstrating the importance of maintaining and monitoring aging infrastructure for climate resilience. With its location in a scenic area of Wyoming, Hanna stands as a testament to the engineering feats of the past and the ongoing efforts to ensure the safety and reliability of water resources in the face of changing climate conditions.
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 Hanna -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Medicine Bow R Ab Seminoe Reservoir | 23 cfs | → |
| Pass Creek Near Elk Mountain | 149 cfs | → |
| L Medicine Bow R At Boles Spring | 9 cfs | → |
| N Platte Riv Ab Seminoe Reservoir | 610 cfs | → |
| Rock Creek Ab King Canyon Canal | 164 cfs | → |
| North Brush Creek Near Saratoga | 136 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Hanna.
⚓ Boat launches
- Shiners Point Road Carbon County
- Carbon County
- East Allen Lake Boat Ramp
- East Allen Lake Boat Launch
- Dugway Campground Boat Takeout
⛺ Campgrounds
- East Allen Lake Public Access - Wgf
- Bow River Ranger Station
- Dugway Campsite 1
- Dugway Campsite 2
- Dugway Campsite 3
- Dugway Campsite 4
🎣 Fishing spots
- East Allen Lake
- Seminoe Reservoir
- Saratoga Lake
- Dome Rock Reservoir
- Pathfinder Reservoir
- Wheatland Reservoir #3
🛶 Paddle runs
More paddle runs →🛡 More reservoirs
More reservoirs →Track Hanna 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 Hanna
Where does the data for Hanna 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 Hanna.