Holter Dam dam
Holter Dam
Holter Dam, located on the Missouri River in Montana, is a gravity dam with a height of 124 feet and a length of 1364 feet. Completed in 1918, this dam serves multiple purposes, including flood risk reduction and hydroelectric power generation. With a normal storage capacity of 245,000 acre-feet and a maximum storage of 306,000 acre-feet, Holter Dam plays a crucial role in managing water resources in the region.
The dam is owned by a private entity and regulated by the Federal Energy Regulatory Commission. With a high hazard potential and a very high risk assessment rating, the safety and management of Holter Dam are of utmost importance. The spillway, with a width of 558 feet, is controlled, and the dam features outlet gates for water release. Despite its age, the dam's condition assessment is not available, highlighting the need for regular inspections and risk management measures.
Holter Dam's location in Lewis and Clark County, Montana, makes it a significant structure in the region's water resource infrastructure. The dam has a controlled spillway and a high hydraulic height of 120 feet, contributing to its flood risk reduction capabilities. As a key hydroelectric facility in the area, the dam provides clean energy while also ensuring water security and flood control for the surrounding communities.
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 Holter Dam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Missouri River Bl Holter Dam Nr Wolf Cr Mt | 3,110 cfs | → |
| Little Prickly Pear Cr At Wolf Cr Mt | 88 cfs | → |
| Dearborn River Near Craig Mt | 326 cfs | → |
| Missouri River Bl Hauser Lake Nr Helena Mt | 3,230 cfs | → |
| Missouri River At Cascade Mt | 3,750 cfs | → |
| Tenmile Creek Near Helena Mt | 34 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Holter Dam.
Boat launches
- Holter Dam Boat Ramp
- Holter Lake Boat Ramp
- Beartooth Road Lewis And Clark County
- Log Gulch Boat Ramp
- Hauser Dam Road Helena Valley Northeast
- White Sandy Boat Ramp
Campgrounds
- Holter Dam
- Holter Lake Campground
- Holter Lake State Rec Area
- Wolf Creek Bridge Fas
- Log Gulch
- Departure Point
Fishing spots
- Dearborn River
- Little Prickly Pear Creek
- Missouri River Fishing Access Site
- Prickly Pear Creek
- Silver Creek
- Alice Creek
Track Holter Dam 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 Holter Dam
Where does the data for Holter Dam 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 High 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 Holter Dam.