HIGH

Weather Hazards & Sea Conditions

Operating safely in severe weather, local wind funnels, and choppy sea states across Prince William Sound.

Weather Challenges in the Sound

Navigating Prince William Sound requires close attention to the region’s climate. Cold air currents pouring off the Chugach glaciers meet maritime winds coming from the Gulf of Alaska, causing volatile marine weather. While summer months (late May through August) often present calm intervals, conditions can deteriorate rapidly. Wind velocities can increase unexpectedly, kicking up steep wave crests as high as 12 feet in exposed sections of the Sound.

Critical Weather Patterns to Monitor

1. Channel Funnels and High Wind Zones

Localized pressure differences, particularly between the Cook Inlet basin and Prince William Sound, generate intense wind patterns through narrow passages:

  • Passage Canal (Whittier to Shotgun Cove): This narrow corridor acts as a major wind funnel. Severe headwinds and steep, short chop are common here. These conditions frequently subside once a vessel rounds Trinity Point or Decision Point into the wider channel.
  • Glacial Winds (Katabatics): Dense, cold air masses sliding off the high glaciers flow downward, pushing strong gusts directly out of glacier-carved inlets.

2. Confused Sea States

Mariners should exercise caution where different water bodies intersect:

  • Southern Port Wells Junction: The intersection of Blackstone Bay, Passage Canal, Cochrane Bay, and Wells Passage creates a meeting place for opposing winds and currents.
  • Chop Dynamics: These clashing weather forces create irregular, steep waves with no uniform direction, resulting in a confused sea state that is challenging for small boats. Similar irregular waves are common inside Blackstone and Icy Bays.
  • Fetch Effects: Strong easterly winds blowing across long stretches of unobstructed water (fetch) build up large, rhythmic swell patterns, resulting in rough conditions across the Sound’s open central basin.

Operating Guidelines for Skippers

  • Maintain Flexible Schedules: Never travel under rigid time constraints. If conditions begin to deteriorate, head to the nearest protected anchorage or beach. It is far safer to wait out a storm on shore than to struggle through rough waters.
  • Communication Update: If you change your route to seek shelter, notify your emergency shore contact immediately with your updated coordinate position.
  • Active Monitoring: Keep a regular watch on changing cloud patterns and listen to maritime weather reports.

Accessing Marine Forecasts in PWS

Always check the active forecast for Zone PKZ724 (Prince William Sound) prior to departure and while underway:

  1. VHF Weather Radio: Monitor WX-2 (common around Whittier and Cordova) or WX-1 (Valdez area) for continuous NOAA updates.
  2. Online Portal: Check updates via www.weather.gov/afc for Passage Canal, Port Valdez, and the open Sound.
  3. Telephone Recorded Updates: Call 1-800-472-0391 using code 3144 (PWS) or 3145 (Passage Canal).
  4. Valdez Weather Station: Contact the NWS office directly at 907-835-4505.
  5. Harbor Offices: Check weather boards at the Whittier Harbormaster’s office (907-472-2330) or the info kiosk in the Whittier Triangle.
  6. Staging Information: Listen to AM 1610 in the Whittier tunnel staging zone.
  7. SSB Broadcasts: Larger vessels can monitor scheduled weather announcements on 4125 kHz.