Susquehanna River at Harrisburg
Pennsylvania · Flood watch
Measured at USGS 01570500 — Susquehanna River at Harrisburg, PA · NWS forecast point HARP1
Reading taken Jul 28, 11:00 PM UTC
Below normal for the date
At 8,070 CFS, this gauge is running 75% of normal for late July — below the 10,800 CFS median USGS has recorded for this date across 135 years of record (1891–2025).
Data-derived guidance from USGS and NWS published values — not official advice, and not a safety assessment.
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Flood stages at Harrisburg
Official National Weather Service categories for gauge HARP1, issued by WFO CTP. Impact statements are the NWS's own wording for this location, reproduced verbatim.
-
Major flood 23.0 ft
- 23.0 ft Evacuations are necessary in the Shipoke area of Harrisburg. Listen to local emergency officials for specific details. The water level reaches the corner of Kelker and Front Streets. Delaware Street, Geiger Street and Maclay Streets may also be impacted.
- 24.0 ft The residential section of Front and Second Streets in Harrisburg flood at this level. Cameron Street in Harrisburg floods due to backwater from Paxton Creek.
- 26.0 ft FEMA 2% Annual Chance Flood Level (50-year flood). Flood waters begin to reach the Walnut Street Bridge. Green and Vaughn Streets flood.
- 28.0 ft Widespread flooding occurs in the residential sections of Front and Second Streets and in the Shipoke area of Harrisburg. Flooding reaches Italian Lake Park in Harrisburg.
- 29.0 ft FEMA 1% Annual Chance Flood Level (100-year flood). Flood waters begin to reach the Market Street Bridge.
- 30.0 ft Widespread flooding occurs on both banks.
- 32.0 ft Widespread flooding occurs on both banks. The square and central business district in Harrisburg begin to be affected.
- 33.3 ft Flood of record from Hurricane Agnes in 1972.
- 35.0 ft Flood waters begin to reach the Harvey Taylor Bridge.
- 37.0 ft FEMA 0.2% Annual Chance Flood Level (500 year flood).
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Moderate flood 20.0 ft
- 20.0 ft Riverfront Park in Harrisburg begins to flood.
- 20.5 ft FEMA 10% Annual Chance Flood Level (10-year flood).
- 21.0 ft Homes on both banks are affected by high water. This is the approximate level of Routes 11 and 15, upstream of the Market Street Bridge. Flood waters begin to reach South Main Street in Marysville.
- 22.5 ft US 22/322 in the vicinity of the Dauphin Narrows is impacted by flood waters.
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Minor flood 17.0 ft
- 17.0 ft Basements of residences and businesses on both banks flood. The parking lot on City Island begins to take on water.
- 19.0 ft A number of homes in West Fairview, Dauphin, and Harrisburg flood. Flood waters begin to reach Front Street in East Pennsboro Township in Cumberland County.
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Action 11.0 ft
- 11.0 ft Recreational use of City Island begins to be curtailed. River interests are encouraged to monitor conditions.
- 13.0 ft The recreation area on City Island is evacuated. River interests are encouraged to monitor conditions.
- 15.0 ft The recreation area of City Island is evacuated. River interests are encouraged to monitor conditions.
- Right now 3.42 ft
NWS forecast: 3.70 ft by Jul 30, 6:00 PM UTC.
12 months of flow at Harrisburg
Daily values from USGS gauge 01570500. Provisional data, subject to revision.
Highest crests on record at Harrisburg
| Stage | Flow | Date |
|---|---|---|
| 33.27 ft | 1,020,000 CFS | Jun 24, 1972 |
| 29.23 ft | 740,000 CFS | Mar 19, 1936 |
| 26.80 ft | 654,000 CFS | Jun 2, 1889 |
| 25.70 ft | 613,000 CFS | May 22, 1894 |
| 25.17 ft | 589,800 CFS | Sep 9, 2011 |
| 25.08 ft | — | Jan 20, 1996 |
| 24.66 ft | 568,000 CFS | Jan 21, 1996 |
| 24.40 ft | — | Sep 19, 2004 |
| 23.81 ft | — | Sep 27, 1975 |
| 21.80 ft | — | May 29, 1946 |
Historical crests published by the National Weather Service for this gauge.
About Susquehanna River at Harrisburg
This is the reference gauge for Susquehanna River at Harrisburg, Pennsylvania. It is the reading local emergency managers, the National Weather Service and residents watch when the river comes up.
Largest flood-watch population on the river.
Raw CFS means little on its own, so every reading on this page is shown against the USGS median for the same calendar day — 10,800 CFS for late July, from 135 years of record.
Because the National Weather Service also operates a forecast point here, the page carries the official flood-category ladder and the NWS's own stage-by-stage impact statements.
Susquehanna River at Harrisburg — common questions
What is the current flow on Susquehanna River at Harrisburg?
As of the last reading on this page, Susquehanna River at Harrisburg was running 8,070 CFS at a gage height of 3.42 ft, or 75% of the USGS median for this date. The number updates automatically from USGS gauge 01570500, which reports every 15 to 60 minutes.
Is that high or low for this time of year?
The USGS median flow for late July at this gauge is 10,800 CFS, calculated from 135 years of record (1891–2025). Comparing today's reading against that median is the only way a raw CFS number tells you anything — 200 CFS is a drought on one river and a flood on another.
How often does this reading update?
USGS transmits from this gauge every 15 to 60 minutes. This page bakes in the most recent reading when it is rebuilt, then refreshes live from USGS when you open it. Readings are provisional and subject to revision by USGS.
What is flood stage at Harrisburg?
The National Weather Service sets minor flood stage at this gauge at 17.0 ft, moderate at 20.0 ft, and major at 23.0 ft. Action stage — the level at which agencies begin preparing — is 11.0 ft. The ladder on this page shows each threshold against the current reading.
What happens at each flood stage here?
The National Weather Service publishes 19 stage-by-stage impact statements for this gauge, describing what specific roads, properties and structures are affected at each level. They are reproduced verbatim on this page, lowest to highest. They are NWS descriptions, not riverlvl's.
Is there a forecast for this gauge?
Yes. This is an NWS forecast point, so the chart shows the observed hydrograph running into the official National Weather Service forecast. Forecasts are issued by the local Weather Forecast Office (CTP) and updated through the day during high water.