Twelve hours at the Whittier Back Channel pull-off
Getting to the pull-off
The Back Channel pull-off is three miles south of the Whittier tunnel exit on the Portage Glacier Highway. There is no sign. Look for a gravel apron on the east side, marked by a single reflector stake and two concrete parking stops half-buried in moss. Arrive ninety minutes before low slack. The window closes fast.
Park facing out. Leave your hazards on. The tunnel operator monitors this stretch and will radio if conditions change, but you will not hear it.
Tide and timing
Low slack at the Back Channel occurs forty-seven minutes after the posted Whittier Harbor time. This is not printed anywhere. You calculate it by hand using the NOAA secondary station offset and a correction factor of 0.83. Write the result on your dashboard in grease pencil. Do not rely on your phone.
The mud flat extends eight hundred yards at full retreat. You have four hours to walk it, photograph it, and return before the bore arrives. The bore is not dangerous if you are paying attention. If you are not paying attention, you will not make it back to the pull-off.
What to carry
Two trekking poles. Neoprene waders, not rubber. A whistle on a breakaway lanyard. One liter of water in an insulated sleeve. A backup insulated sleeve. A laminated photocopy of the secondary station offset table, hole-punched and clipped to your jacket with a carabiner.
Two headlamps, fresh batteries in both. A third headlamp in your pack. Spare AAAs in a Ziploc, labeled with the purchase date. A small notepad to record the actual low slack time when you reach the farthest exposed stone. This is for your records.
Hand warmers, six pairs. A space blanket. A second space blanket. Fifty feet of 6mm accessory cord, precut, ends melted. You will not need it, but you will carry it.
The twelve-hour block
You arrive ninety minutes early. You walk the flat for four hours. You return to the pull-off and eat in the car with the engine running. You document the tide return from the driver's seat for two hours. You drive back through the tunnel during the next outbound window, which opens four hours after you finish eating.
This is twelve hours. Do not compress it. The Back Channel is not a stop on the way to somewhere else.
What you will see
Stone ribs running parallel to the shore. Kelp holdfasts dry and clicking in the wind. The far side of the channel is a shale face that has never been climbed. At the farthest point, you will find a single piling, rusted through, tilted fifteen degrees to the south. No one knows what it held.
The bore returns as a line, then a sound, then a wall. You will already be back at the car.
Booking the tunnel
The Whittier tunnel runs on a fixed schedule. Outbound windows from Whittier are posted online, but the site does not account for the twelve-hour block. Call the tunnel operator forty-eight hours in advance and say you are planning a full-day pull-off observation. They will note it. This is not a reservation, but it is better than nothing.
If you are staging from Anchorage, add two hours of drive time each way. If you are staging from Girdwood, review the Girdwood South Ridge timing framework to avoid overlapping your tunnel window with an active ridge departure.
After
You will drive back through the tunnel in silence. You will not stop in Whittier. The twelve hours are complete when you pass the reflector stake on your return and do not look back.