Helm Rock tidal current predictions

Now

Flood 1.2 ktToward ENE (74°)

Next slack

11:34 PMAKDT

Next max flood

1.7 ktSat 8:36 AM

Next max ebb

3.3 ktSat 3:24 AM

Knots along the channel: above the line the flood, running in toward ENE (74°); below it the ebb, running out toward WSW (240°). Times are Alaska Daylight Time. Today: ebb 3.0 kt 2:47 AM, slack 6:21 AM, flood 1.2 kt 8:01 AM, slack 11:27 AM, ebb 3.3 kt 3:09 PM, slack 6:43 PM, flood 1.3 kt 8:20 PM, slack 11:34 PM.

None right now. The National Weather Service issues small craft advisories, gale and storm warnings, special marine warnings, dense fog advisories and coastal flood products for water like this.

The flood is the tidal current running in from the sea, the ebb the current running back out. Slack water is the short turn between them, when the current is weakest: the time to cross a strong channel, anchor, or dive. Slack in a channel is not the time of high or low tide; it can come hours after.

Speeds are knots along the channel's main axis, and directions are degrees true toward which the water flows, as NOAA prints its tables. A current against the wind stands the waves up steep and close together.

Predictions are astronomical: the moon and the sun, not the weather. Strong wind, river flow after heavy rain and storm surge all change the real current.

• Sumner Island, east ofHarmonic current station3.7 mi
• Mariposa Reef, 3 miles south ofHarmonic current station3.8 mi
• Sumner Island, 1.8 miles south ofSubordinate current station5.7 mi
• Calder RocksHarmonic current station9.8 mi
• Beauclerc Island Light, 1 mile east ofSubordinate current station10 mi
• Southern entrance to Keku StraitSubordinate current station13 mi
• Red Bay EntranceHarmonic current station14 mi
• Shakan Light, 2.8 miles WNW ofSubordinate current station14 mi

• Tide times at Port Protection, Prince of Wales Island 5.3 mi
• Tide times at Sumner Island 5.4 mi
• Tide times at Reid Bay 8.3 mi
• Open the live map with tidal currents
• All tidal current stations in Alaska

Tidal current predictions from NOAA’s Center for Operational Oceanographic Products and Services (CO-OPS), station SEA0604, bin 12: original at NOAA. Marine alerts from the National Weather Service.