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Ramapo River at Mahwah

Highest listed crest 15.78 ftFlood stage 8.0 ft22 crests since 1938

The Ramapo River at Mahwah crested at major flood stage 3 times among the 22 crests the National Weather Service lists from 1938 to 2011. The highest, 15.78 ft on August 28, 2011, was major flooding, 7.78 feet above flood stage. 1 other gauge on the Ramapo River crested above flood stage within a week of it, 1 at its own highest listed crest.

The gauge

Highest listed crest
15.78 ft
August 28, 2011
Flood stage
8.0 ft
Major flooding from 12.0 ft
Crests at major
3
39th of 125 gauges in New Jersey
Most recent flood crest
August 28, 2011
15.78 ft, major flooding
Location
Bergen County
Near Suffern (1.5 mi), Ramsey (2.6 mi), Airmont (3.4 mi)

Flood stages

The thresholds the National Weather Service uses for this gauge today, and how many listed crests reached each.

Flood categories, Ramapo River at Mahwah
Action stage7.50—The level at which the NWS or its partners begin to take action
Flood stage (minor)8.06Dec 12, 2008Minimal or no property damage, but possibly some public threat
Moderate flood stage9.013Apr 17, 2011Some inundation of structures and roads near the stream
Major flood stage12.03Aug 28, 2011Extensive inundation of structures and roads

Every listed crest

22 crests from 1938 to 2011. Filled: at or above flood stage. Hover a crest for its date and stage.

Listed crests at the Ramapo River at Mahwah, 1938 to 2011 810121416ft Flood stage 8.0 ftMajor 12.0 ft Sep 22, 1938: 10.40 ft, moderate flooding; 6,720 cubic feet per secondAug 19, 1955: 11.35 ft, moderate flooding; 8,580 cubic feet per secondOct 16, 1955: 12.53 ft, major flooding; 10,900 cubic feet per secondDec 21, 1957: 9.33 ft, moderate flooding; 3,800 cubic feet per secondFeb 26, 1961: 8.87 ft, minor flooding; 3,120 cubic feet per secondMay 29, 1968: 11.87 ft, moderate flooding; 8,770 cubic feet per secondAug 28, 1971: 10.76 ft, moderate flooding; 6,700 cubic feet per secondFeb 3, 1973: 9.77 ft, moderate flooding; 4,340 cubic feet per secondDec 21, 1973: 10.50 ft, moderate flooding; 6,050 cubic feet per secondJan 25, 1979: 9.90 ft, moderate flooding; 4,750 cubic feet per secondJan 5, 1982: 8.40 ft, minor flooding; 2,520 cubic feet per secondNov 12, 1995: 8.88 ft, minor flooding; 4,330 cubic feet per secondJan 25, 1996: 8.69 ft, minor flooding; 3,420 cubic feet per secondSep 16, 1999: 12.52 ft, major flooding; 13,800 cubic feet per secondDec 11, 2003: 8.80 ft, minor flooding; 4,200 cubic feet per secondApr 3, 2005: 9.87 ft, moderate flooding; 6,220 cubic feet per secondOct 13, 2005: 9.85 ft, moderate flooding; 6,170 cubic feet per secondDec 12, 2008: 8.07 ft, minor flooding; 3,090 cubic feet per secondMar 7, 2011: 11.16 ft, moderate floodingMar 11, 2011: 10.72 ft, moderate floodingApr 17, 2011: 9.55 ft, moderate flooding; 5,520 cubic feet per secondAug 28, 2011: 15.78 ft, major flooding Highest, 15.78 ft, Aug 28, 2011 19401950196019701980199020002010

Crests at or above flood stage, by decade

Crests at or above flood stage per decade, Ramapo River at Mahwah 1930s: 1 1940s: 0 1950s: 3 1960s: 2 1970s: 4 4 1980s: 1 1990s: 3 2000s: 4 2010s: 4 1930s1940s1950s1960s1970s1980s1990s2000s2010s
  1. These are the crests the local National Weather Service office lists for the gauge: the highest on record and recent crests. Lesser floods between them may be missing, so counts by decade are a floor.
  2. Categories use today's flood stages. Levees, dams and channel changes since a crest can make old and new stages not directly comparable.
  3. 1 crest measured on an earlier gauge datum is left out: 11.00 ft on Oct 9, 1903.

Highest crests

Highest listed crests, Ramapo River at Mahwah
1Aug 28, 201115.78+7.78Major—
2Oct 16, 195512.53+4.53Major10,900
3Sep 16, 199912.52+4.52Major13,800
4May 29, 196811.87+3.87Moderate8,770
5Aug 19, 195511.35+3.35Moderate8,580
6Mar 7, 201111.16+3.16Moderate—
7Aug 28, 197110.76+2.76Moderate6,700
8Mar 11, 201110.72+2.72Moderate—
9Dec 21, 197310.50+2.50Moderate6,050
10Sep 22, 193810.40+2.40Moderate6,720
11Jan 25, 19799.90+1.90Moderate4,750
12Apr 3, 20059.87+1.87Moderate6,220
13Oct 13, 20059.85+1.85Moderate6,170
14Feb 3, 19739.77+1.77Moderate4,340
15Apr 17, 20119.55+1.55Moderate5,520
16Dec 21, 19579.33+1.33Moderate3,800
17Nov 12, 19958.88+0.88Minor4,330
18Feb 26, 19618.87+0.87Minor3,120
19Dec 11, 20038.80+0.80Minor4,200
20Jan 25, 19968.69+0.69Minor3,420
21Jan 5, 19828.40+0.40Minor2,520
22Dec 12, 20088.07+0.07Minor3,090

The worst floods along the Ramapo River

For this gauge's highest crests, the other gauges on the Ramapo River that crested above flood stage within a week.

August 28, 2011: 15.78 ft here, major flooding

  • Pompton LakesNJ · Aug 29, 2011 · 22.62 ft · Major · its highest

September 16, 1999: 12.52 ft here, major flooding

  • SuffernNY · Sep 16, 1999 · 15.23 ft · Minor

Gauges on the Ramapo River

In USGS station-number order, which runs downstream within a river basin.

Flood gauges on the Ramapo River
SuffernNY15.215.38 ft, Apr 5, 19840
Mahwah this gaugeNJ8.015.78 ft, Aug 28, 20113
Pompton LakesNJ11.522.62 ft, Aug 29, 20119

Other gauges in Bergen County

Flood gauges in Bergen County
New Milford6.012.36 ft, Apr 16, 20072
Rivervale5.512.26 ft, Aug 28, 20113
Ho-Ho-Kus3.07.32 ft, Sep 16, 19992
Westwood5.011.40 ft, Sep 16, 19991
Lodi5.513.94 ft, Sep 16, 199916
Ridgewood5.011.42 ft, Aug 28, 20111
Upper Saddle River4.55.64 ft, Sep 16, 19991

Bergen County: every hazard · River floods across the country · New Jersey

NOAA National Water Prediction Service, gauge MAWN4, retrieved October 30, 2026. Stages in feet on the gauge's own datum, not elevation. Crests are as the National Weather Service lists them; preliminary values may be revised.