O'Halloran dam
O'Halloran
O'Halloran, also known as Lower O'Halloran, is a privately owned irrigation dam located in Clyde Park, Montana. Built in 1960 on Looking Glass Creek, this Earth-type dam stands at 23 feet high and has a storage capacity of 149 acre-feet. Its primary purpose is to support irrigation activities in the area, providing water for agricultural use.
Managed by the Montana Department of Natural Resources and Conservation (DNRC), O'Halloran is considered to have a significant hazard potential. Despite its age, the dam's condition assessment is currently not rated, raising concerns about its long-term safety and maintenance. While it has not been inspected recently, the state does have regulatory oversight, permitting, and enforcement authority over the structure.
Located in Park County, Montana, O'Halloran serves as a vital water resource for the surrounding agricultural community. With its strategic position on Looking Glass Creek and support for irrigation needs, it plays a crucial role in sustaining local farming operations. As climate change continues to impact water resources, the proper management and upkeep of dams like O'Halloran are essential to ensure water availability for future generations.
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 O'Halloran -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Shields River Nr Livingston Mt | 293 cfs | → |
| Yellowstone River Near Livingston Mt | 6,770 cfs | → |
| Hyalite C At Hyalite R S Nr Bozeman Mt | 44 cfs | → |
| Boulder River At Big Timber Mt | 859 cfs | → |
| Gallatin River At Logan Mt | 1,180 cfs | → |
| South Fork Musselshell R Ab Martinsdale Mt | 43 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near O'Halloran.
Boat launches
- Us 89 Park County
- Park County
- East River Road Park County
- Pine Creek Road Park County
- North Yellowstone Trail Road Sweet Grass County
Campgrounds
Fishing spots
Paddle runs
- Gallatin Forest Boundary, Sec. 26, T3s, R12e To Blakley Creek, Sec. 26, T3s, R12e
- Blakley Creek, Sec. 26, T4s, R12e To Miller Creek, Sec 13, T4s, R21e
- Miller Creek, Sec. 13, T4s, R21e To Bramble Creek, Sec. 26, T5s, R12e
- Bible Run
- Bramble Creek, Sec. 26, T5s, R12e To Absaroka-Beartooth Wilderness, Sec. 22, T7s, R12e
- Moose To Storm Castle
More reservoirs
Track O'Halloran 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 O'Halloran
Where does the data for O'Halloran 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 Significant 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 O'Halloran.