Dam Report

Howard A. Hanson Dam dam

Washington, USA Green Hazard High
Today high
--
Tonight low
--
Dam height
235ft
Hazard rating
High
Loading current conditions…
Loading next 24 hours…
Loading 7-day outlook…
Howard A. Hanson Dam -- None dam
Howard A. Hanson Dam None · Green
About this dam

Howard A. Hanson Dam

Howard A. Hanson Dam, located in Auburn, Washington, is a rockfill dam primarily designed for flood risk reduction along the Green River. Completed in 1962 by the US Army Corps of Engineers (USACE), the dam has a hydraulic height of 220 feet and a structural height of 235 feet, with a maximum storage capacity of 136,700 acre-feet. While the dam plays a crucial role in reducing flood risks, extreme rainfall events could still necessitate controlled releases through the outlet tunnel or spillway to prevent overtopping and potential failure.

USACE has implemented numerous risk management measures to ensure the dam's safety and reduce risks to life safety and property. This includes regular inspections, monitoring instrumentation, and maintenance activities to address any potential concerns. The agency also collaborates with local emergency managers to update the Emergency Action Plan annually, conducts emergency exercises, and hosts stakeholder meetings to keep the community informed. Despite the low likelihood of dam failure scenarios, USACE remains committed to safeguarding the dam and mitigating potential risks to downstream communities in Auburn, Kent, and beyond.

Overall, Howard A. Hanson Dam remains a vital infrastructure for flood risk reduction in the region, with USACE's ongoing efforts to maintain the dam's integrity and ensure its resilience in the face of extreme weather events. Through continuous monitoring, maintenance, and collaboration with local authorities, the dam serves as a critical asset in protecting communities from potential flooding disasters.

StateNone
River / streamGreen
NID IDWA00298
Owner typeFederal
Primary purposeFlood Risk Reduction
Dam typeRockfill
Year built1962
Dam length500 ft
Max storage136,700 AF
Normal storage26,000 AF
Surface area20,000.0 ac
Drainage area221.0 sq mi
Hazard potentialHigh
ConditionNot Available
Last inspectionFri, 08 Oct 2021 11:00:00 GMT
EAP preparedYes

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.
Detailed forecast

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.

Hourly detail

Next 5 days, hour by hour

Temperature line with weather symbols on top, snow + rain accumulation as columns, humidity as a dotted line.

Loading hourly forecast…
Deep dive

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.

TimeConditionTemp (°F)Snow (in)Rain (in)Humidity (%)Wind (mps)Wind dir
Loading detailed forecast…
Long-term outlook

15-day temperature & precipitation

Daily temperatures, snow, and rain projected over the next two weeks.

Loading 15-day outlook…
Regional inflow

Nearby streamflow gauges

USGS streamgauges around Howard A. Hanson Dam -- inflows here typically show up in storage 24-72 hours later.

Track Howard A. Hanson 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.

FAQ

About Howard A. Hanson Dam

Where does the data for Howard A. Hanson 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.