Flood Warning Issued for Johnson Creek Affecting Clackamas and Multnomah Counties

Source: NOAA · Clackamas and Multnomah Counties, Oregon

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NWS Portland has issued a Flood Warning for Johnson Creek at Sycamore, where minor flooding is forecast to reach 11.3 feet by late Thursday afternoon.

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

This notice was issued by NOAA on March 24, 2026 and geographically references Clackamas and Multnomah Counties, Oregon. 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 regulatory framework behind it, which shapes what remedies (refunds, replacements, recalls, evacuations) are available to affected individuals and who holds statutory responsibility for enforcement.

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.

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Alert Details

The National Weather Service in Portland, OR, has issued a Flood Warning for Johnson Creek at Sycamore. This alert replaces the previous River Flood Watch for the area.

Affected Areas

The warning specifically impacts Clackamas and Multnomah Counties in Oregon. Minor flooding is expected along Johnson Creek, particularly in the areas between SE 92nd Street and SE 122nd Street, as well as the region between Johnson Creek and SE Harold Street.

What You Should Do

Residents and motorists are urged to follow the "Turn around, don't drown" rule when encountering flooded roads. Most flood-related deaths occur in vehicles. Do not attempt to drive around barricades or through flooded areas.

Expected Conditions

Minor flooding is forecast as the river rises. As of 8:30 AM PDT on Thursday, the river stage was measured at 9.4 feet. The bankfull stage is 10.0 feet, while the flood stage is 11.0 feet. The river is forecast to rise to a maximum value of 11.3 feet late this afternoon.

Timeline

The Flood Warning is effective as of 9:01 AM PDT on March 12, 2026. The onset of flooding conditions is expected at 11:00 AM PDT today. The warning remains in effect until 5:00 AM PDT on Saturday, March 14, 2026.

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?
NWS Portland has issued a Flood Warning for Johnson Creek at Sycamore, where minor flooding is forecast to reach 11.3 feet by late Thursday afternoon.
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 Clackamas and Multnomah Counties, Oregon. 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.