Calder Rocks tidal current predictions

Now

Flood 0.4 ktToward N (9°)

Next slack

Sat 12:11 AMAKDT

Next max flood

0.4 kt9:54 PM

Next max ebb

0.6 ktSat 3:20 AM

Knots along the channel: above the line the flood, running in toward N (9°); below it the ebb, running out toward SSW (198°). Times are Alaska Daylight Time. Today: ebb 0.5 kt 2:47 AM, slack 5:05 AM, flood 0.4 kt 9:24 AM, slack 11:45 AM, ebb 0.6 kt 3:03 PM, slack 5:31 PM, flood 0.4 kt 9:54 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.

• Beauclerc Island Light, 1 mile east ofSubordinate current station3.0 mi
• Shakan Light, 2.8 miles WNW ofSubordinate current station5.3 mi
• Amelius Island, 1 mile east ofHarmonic current station5.8 mi
• Mariposa Reef, 3 miles south ofHarmonic current station6.4 mi
• Shakan Light, 2.4 miles west ofHarmonic current station6.7 mi
• Sumner Island, 1.8 miles south ofSubordinate current station9.2 mi
• Helm RockHarmonic current station9.8 mi
• Shakan Strait, west endHarmonic current station9.9 mi

• Tide times at Port Protection, Prince of Wales Island 7.2 mi
• Tide times at Shakan Bay Entrance 8.5 mi
• Tide times at Port Beauclerc, Kuiu Island 9.2 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 SEA0608, bin 9: original at NOAA. Marine alerts from the National Weather Service.