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Merrimack River at Nashua
Critical Stages
16' - Action
18' - Flood
26' - Moderate
35' - Major
Latest Observation
Updated: 8:15 PM EST 12/5/25
Status: No Flooding
Stage: 4.74 ft
Flow: 3.06 kcfs
Forecast
| Time | Stage (ft) | Flow (kcfs) |
|---|---|---|
| 1 AM 12/6 | 4.5 | 2.1 |
| 7 AM 12/6 | 4.5 | 2.1 |
| 1 PM 12/6 | 4.5 | 2.1 |
| 7 PM 12/6 | 4.5 | 2.1 |
| 1 AM 12/7 | 4.5 | 2.1 |
| 7 AM 12/7 | 4.5 | 2.1 |
| 1 PM 12/7 | 4.5 | 2.1 |
| 7 PM 12/7 | 4.5 | 2.1 |
| 1 AM 12/8 | 4.5 | 2.1 |
| 7 AM 12/8 | 4.5 | 2.1 |
| Time | Stage (ft) | Flow (kcfs) |
|---|---|---|
| 9:15 PM 12/5 | 4.72 | 2.97 |
| 9:00 PM 12/5 | 4.73 | 3.01 |
| 8:45 PM 12/5 | 4.72 | 2.97 |
| 8:30 PM 12/5 | 4.73 | 3.01 |
| 8:15 PM 12/5 | 4.74 | 3.06 |
| 8:00 PM 12/5 | 4.74 | 3.06 |
| 7:45 PM 12/5 | 4.74 | 3.06 |
| 7:30 PM 12/5 | 4.73 | 3.01 |
| 7:15 PM 12/5 | 4.75 | 3.11 |
| 7:00 PM 12/5 | 4.73 | 3.01 |
| 6:45 PM 12/5 | 4.75 | 3.11 |
| 6:30 PM 12/5 | 4.75 | 3.11 |
| 6:15 PM 12/5 | 4.75 | 3.11 |
| 6:00 PM 12/5 | 4.75 | 3.11 |
| 5:45 PM 12/5 | 4.74 | 3.06 |
| 5:30 PM 12/5 | 4.74 | 3.06 |
| 5:15 PM 12/5 | 4.74 | 3.06 |
| 5:00 PM 12/5 | 4.74 | 3.06 |
| 4:45 PM 12/5 | 4.73 | 3.01 |
| 4:30 PM 12/5 | 4.73 | 3.01 |
| 4:15 PM 12/5 | 4.7 | 2.88 |
| 4:00 PM 12/5 | 4.66 | 2.71 |
| 3:45 PM 12/5 | 4.67 | 2.75 |
| 3:30 PM 12/5 | 4.68 | 2.79 |
| 3:15 PM 12/5 | 4.66 | 2.71 |
| 3:00 PM 12/5 | 4.67 | 2.75 |
| 2:45 PM 12/5 | 4.66 | 2.71 |
| 2:30 PM 12/5 | 4.67 | 2.75 |
| 2:15 PM 12/5 | 4.66 | 2.71 |
| 2:00 PM 12/5 | 4.66 | 2.71 |
40' -
This is a disastrous...life threatening flood. This compares to the Great New England Flood of 1936. Follow the advice of local officials...and evacuate if told to do so.
35' -
This is a major...life threatening flood event. The river has not reached this height since the Great New England flood of 1936. Major flooding will affect the communities of Merrimack and Litchfield through Nashua and Hudson. follow the advice of local officials...evacuate if told to do so. Stay away from the Merrimack River.
30' -
This flood compares to the Hurricane of 1938 flood. This is a substantial flood event. Follow the directions of local officials...evacuate if told to do so. At this height the Merrimack River is moving very swiftly. Stay away from the river.
28' -
The river has not reached this height since the Hurricane of 1938. This is a serious flood event. Follow the advice of local officials...evacuate if told to do so. At this height...the Merrimack River is moving very swiftly. Stay away from the river.
25' -
The river has not reached this height since May 2006. This is a significant flood event. Follow the advice of local officials...evacuate if told to do so.
21' -
Flooding will occur in low lying areas from Litchfield and Merrimack...to Hudson and Nashua.
18' -
Flooding will begin in the lower lying sections of Hudson and Nashua as the river continues to climb above 18 feet.
| Date | Stage (ft) |
|---|---|
| Mar 20, 1936 | 41.3 |
| Sep 23, 1938 | 30.5 |
| May 15, 2006 | 26 |
| Apr 17, 2007 | 23.5 |
| Apr 7, 1987 | 22.4 |
| Apr 18, 1996 | 19 |
| Apr 1, 2010 | 18.81 |
| Mar 28, 1953 | 18.4 |
| Oct 22, 1996 | 18.1 |
| Apr 14, 1940 | 18.1 |
| Apr 4, 1952 | 17 |
| Jun 17, 1998 | 17 |
| Apr 4, 1951 | 17 |
| Apr 1, 1993 | 16.2 |
| Apr 23, 1969 | 15.6 |
| Apr 20, 1997 | 15.6 |
| Apr 13, 1993 | 15.5 |
| Mar 23, 1948 | 15.3 |
| Apr 2, 2004 | 14.5 |
| Mar 28, 1968 | 14.2 |
Data provided by the National Weather Service.
