Kelvin Waves Will Raise West Coast Sea Levels

Warm water pulses moving along the shoreline are expected to lift sea levels by up to a foot this month.

Updated on Oct. 8, 2026 in Forecasts

Turbulent ocean waves break against rocky shoreline cliffs along the Pacific coast. — A strong El Nino event is fueling Kelvin waves along the U.S. West Coast, with sea levels expected to rise by a foot this October. AI Illustration. Upload story photo >

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During October 2026, the West Coast will see sea levels rise by up to a foot due to Kelvin waves. These pulses of warm water intensify as they travel north along the coastline.

Why it matters

The current super El Nino event is strengthening these water bulges, significantly increasing the immediate risks of beach erosion and coastal flooding. The phenomenon shifts water masses toward the shore, creating measurable changes in ocean height.

Sea levels along the West Coast are projected to rise by a maximum of 1 foot throughout October 2026. This elevation is driven by Kelvin waves, which manifest as large bulges of warm water moving north along the shoreline.

The details

Kelvin waves act as pulses of warm water that travel along the coast, effectively lifting the sea surface. These bulges accumulate as they move, creating a temporary but significant rise in water levels across the region.

October 2026 marks the period when West Coast sea levels will rise.

Seasonal Patterns

This month's forecast follows a pattern of heightened sea level variance set by the historical impact of the 1997-1998 super El Nino. The current super El Nino creates conditions where these oceanic bulges reach higher magnitudes than standard seasonal cycles.

Coastal residents should prepare for an increased risk of beach erosion and localized flooding throughout the month. Monitor local alerts for potential water ingress in low-lying areas and follow guidance from local emergency management offices.

The takeaway

Understanding these oceanic pulses is critical for managing coastal property risks during active El Nino cycles. Preparing for temporary water level increases can help mitigate damage to shoreline infrastructure.