Flood Warning Issued for Pike County, Illinois and Marion County, Missouri

Source: NOAA · Pike County, Illinois and Marion County, Missouri

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The National Weather Service has issued a Flood Warning for Pike County in Illinois and Marion County in Missouri, with minor flooding expected along the Mississippi River at Hannibal from Monday afternoon until April 19.

What this NWS weather alert tells you, and what most readers miss

This notice was issued by NOAA on April 11, 2026 and geographically references Pike County, Illinois and Marion County, Missouri. Its severity classification of "high" signals how the issuing agency weighs the risk of harm if no action is taken - "critical" and "high" tier alerts typically carry direct consumer actions, while "medium" and "low" tend toward informational guidance or monitoring advisories. The category it belongs to - Weather Alerts - determines the warning protocol behind it, which shapes what protective action (seeking shelter, following evacuation orders if issued, monitoring official updates) is recommended and which agency holds authority to issue or cancel it.

Most readers skim a notice like this, check whether they are personally affected, and move on. The more useful lens is to read it as a data point about the issuing system: how quickly NOAA detected the hazard, how precise the geographic or product-identifier scope is, and whether similar notices have clustered in the same category or region in the last 90 days. Cluster patterns frequently precede a broader regulatory action, a single localized NWS weather alert is isolated; three of them within a quarter often indicate a supply-chain, infrastructure, or seasonal driver that will keep producing notices until something structural changes.

For decision-making, Areazine pairs each alert with the original agency URL, the full agency name, and a timestamp so you can verify the notice against the primary source before acting on it. Tags on this item (weather, alert, Flood Warning, Pike IL Marion MO) map to related alerts in the same area of risk - browsing them together gives a clearer picture than any single notice alone, because the shape of an ongoing issue only becomes visible across multiple sequential alerts.

Flood Warning in Pike and Marion Counties

Alert Details

A Flood Warning has been issued by the National Weather Service in St Louis, MO. It is effective from April 11, 2026, and remains in place until April 19, 2026.

Affected Areas

The warning affects Pike County in Illinois and Marion County in Missouri, specifically along the Mississippi River at Hannibal.

What You Should Do

Motorists should not attempt to drive around barricades or drive cars through flooded areas to ensure safety.

Expected Conditions

Minor flooding is forecast. The river stage was 16.7 feet at 11:15 AM CDT on April 11, and it is expected to rise above the flood stage of 17.0 feet to a crest of 17.5 feet on Wednesday morning. At 17.0 feet, the John Hay Recreation Area on the east side begins flooding.

Timeline

The onset of flooding is expected on Monday afternoon, April 13, 2026. The warning expires on April 12, 2026, at 11:45 PM CDT, and the event ends on April 19, 2026, at 1:00 AM CDT.

Original source: NOAA Official Notice ↗

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Frequently Asked Questions

Common questions about this NWS weather alert.

What is this NWS weather alert about?
The National Weather Service has issued a Flood Warning for Pike County in Illinois and Marion County in Missouri, with minor flooding expected along the Mississippi River at Hannibal from Monday afternoon until April 19.
Which agency issued this alert?
This alert was issued by NOAA. The original notice is available at the source link at the bottom of this article.
How severe is this alert?
This alert is classified as "high" severity. Take precautions and monitor for updates.
What area is affected?
This alert affects Pike County, Illinois and Marion County, Missouri. Check with NOAA for the most current geographic scope.
Where can I find more Weather Alerts updates?
Browse the full Weather Alerts feed on Areazine at areazine.com/weather/ for the latest updates from NOAA and other agencies.