These similar terms describe different water levels. Knowing the difference helps you read coastal flood forecasts.
Storm surge
Storm surge is the abnormal rise in sea level caused by a storm, measured above the water level that would occur without the storm.
Storm tide
Storm tide is the actual water level produced by storm surge combined with the astronomical tide. The timing of high tide therefore matters.
Why local forecasts matter
Coastal shape, seafloor depth, storm size and motion all influence inundation. Check NHC surge products and local evacuation advice, not a hurricane category alone.
Frequently asked questions
Is storm surge the same as wave height?
No. Surge is a rise in the underlying water level. Waves can ride on top of that elevated water and create additional damage.
Why does high tide matter?
If surge arrives near astronomical high tide, the total storm tide can be higher than if the same surge arrives near low tide.
Can category predict surge height?
No. NHC explains that storm size, track, coastal shape, seafloor depth and other factors also affect inundation.
Reviewed 2026-09-28. Independent guide; follow NHC and local authorities for safety decisions.