Frost-Willow Island, between tidal current predictions

Next slack

2:23 AMPDT

Next max flood

0.4 kt4:22 AM

Next max ebb

1.0 kt9:35 AM

Knots along the channel: above the line the flood, running in toward N (10°); below it the ebb, running out toward SE (126°). Times are Pacific Daylight Time. Today: slack 2:23 AM, flood 0.4 kt 4:22 AM, slack 5:39 AM, ebb 1.0 kt 9:35 AM, slack 1:51 PM, flood 0.8 kt 4:42 PM, slack 6:40 PM, ebb 1.1 kt 10:23 PM.

• Small Craft Advisory Small Craft Advisory issued September 25 at 9:58PM PDT until September 26 at 5:00AM PDT by NWS Seattle WAUntil 5:00 AM
  Full text

  * WHAT...Southwest winds 20 to 30 kt. * WHERE...Northern Inland Waters Including The San Juan Islands. * WHEN...Until 5 AM PDT Saturday. * IMPACTS...Conditions will be hazardous to small craft.

  A Small Craft Advisory means that wind speeds of 21 to 33 knots and/or seas 10 feet or higher are expected to produce hazardous wave conditions to small craft. Inexperienced mariners, especially those operating smaller vessels should avoid navigating in these conditions.

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. This is a subordinate station: NOAA predicts it from a nearby harmonic station by fixed corrections to the times and speeds of its slack waters and maxima, so the curve between them is less exact.

• Thatcher PassHarmonic current station1.5 mi
• Fauntleroy Point Light, east ofHarmonic current station3.0 mi
• Peavine Pass, west entranceHarmonic current station3.4 mi
• Strawberry Island, west ofHarmonic current station3.8 mi
• Lopez PassHarmonic current station4.1 mi
• Upright Channel narrowsHarmonic current station4.3 mi
• Obstruction Pass, north of Obstruction IslandHarmonic current station4.5 mi
• Harney Channel, north of Point HudsonHarmonic current station5.4 mi

• Tide times at Armitage Island, Thatcher Pass 1.6 mi
• Tide times at Upright Head, Lopez Island 3.3 mi
• Tide times at Peavine Pass 4.4 mi
• Forecast for Friday Harbor, WA
• Open the live map with tidal currents
• All tidal current stations in Washington

Tidal current predictions from NOAA’s Center for Operational Oceanographic Products and Services (CO-OPS), station PCT2046, bin 1: original at NOAA. Marine alerts from the National Weather Service.