Winds and Currents of Southeast Alaska

Those who navigate any kind of vessel through the waterways of Southeast Alaska should know a few things about wind and ocean currents in the region.

Wind Speed

Wind Direction

The likelihood of east winds and west winds depends on the season. From early April to early November, winds come from the west about 45% of the time. During the remaining period, early November to early April, winds come from the east about 45% of the time. Of course, there is a gradual transition between these periods. Like wind speed, wind direction at any particular location is influenced by topography. Nearby mountains may block, divert, or funnel winds on a regular basis.

Afternoon Winds in the Summer

At times, winds change quickly which can create difficult conditions for boating. At some locations, winds may increase to 30 or 40 miles per hour in the afternoon. If this wind is blowing against a strong tidal current, it may create standing waves. As mentioned, mountains and valleys may funnel and concentrate the winds. The combination of these factors can cause dangerous conditions for navigation, especially for smaller vessels.

Currents

Non-Tidal Currents

Tidal Currents

Main Travel Routes with Potentially Dangerous Currents       
------- ------------ -----------------------------------

Wrangell Narrows — Ferry route to Petersburg
Peril Strait / Sergius Narrows — Ferry route to Sitka
Grenville Channel — South of Prince Rupert BC
  Other Routes — Less Dangerous Currents or Less Traveled      
---------------------------------------------------------
Lituya Bay
— Entrance at Harbor Point
North and South Inian Pass
— West of Icy Strait
Icy Strait
— North Passage and South Passage
Sitakaday Narrows
— South end of Glacier Bay
Stephens Passage
— Southeast of Juneau, between mainland and Grand Island
Snow Passage
— SW edge of Zarembo Island, east of Prince of Wales Island
Eastern Passage / Blake Passage
— From Wrangell southeast to Ernest Sound
Angoon
— Entrance to Kootznahoo Inlet
Chatham Strait
— Between Baranoff Island and Admiralty Island
Keku Strait
— Between Kupreanof Island and Kuiu Island
Stikine Strait
— Between Zarembo Island and Etolin Island
El Capitan Passage
— Between Prince of Wales Island and north side of Kosciusko Island
Tonowek Narrows
— Between west side of Prince of Wales Island and Heceta Island
Tlevak Narrows
— Between Prince of Wales Island and northern tip of Dall Island

Tidal Rapids

Experienced boaters and mariners who travel the Inside Passage are very aware of the location of tidal rapids. Several of these dangerous passages are located on busy travel routes northeast of Vancouver Island.

  Tidal Rapids near Vancouver Island
---------------------------------------
Seymour Narrows — up to 16 knots
Surge Narrows / Okisolo Wave
Hole-in-the-Wall Rapids
Dent Rapids / Gillard Passage / Yuculta Rapids - 10 to 12 knots
Greene Point Rapids
Whirlpool Rapids

The safest time to travel through tidal rapids is during slack tide or at least when flows are at lower velocity and in a favorable direction. Plan ahead and time your arrival for when currents are most favorable. For this, you definitely need to consult current-prediction tables.

It’s also wise to think of strategies to deal with conditions that are worse than expected. For example, ahead of time, find out if there is a safe place to get out of rough water. There might be a side channel or other protected area where winds and currents are less.

During the summer, remember that west winds may develop in the afternoon and change the situation. So pay attention to changes in the wind.

Special Places for Kayakers and Seals

In southeast Alaska, there are dozens of other tidal rapids in obscure places, frequented mainly by seals. These locations will probably remain secret and undiscovered for the foreseeable future due to their extreme remoteness.