← Coast Conditions

Guide

Road closures on this coast

Checked September 18, 2026 against Caltrans District 1, the California Highway Patrol, Humboldt County and Del Norte County.

The Highways tile repeats what Caltrans publishes about the roads these towns depend on. On this coast most of them have no alternative: one highway runs the length of it, and the ways inland are few enough to name. That is what makes a closure here different from a closure somewhere with a grid.

The roads this board watches

Caltrans District 1 covers Del Norte, Humboldt, Mendocino and Lake counties. Two of its routes carry this coast, and those are the two the tile reads.

RouteRuns
US 101the spine: from the state line through Crescent City and Klamath, past Orick and Trinidad to Arcata and Eureka, then Fortuna and south past Garberville
US 199Crescent City up the Smith River to the state line — the inland way out, and the only alternative to 101 when the coast road shuts
SR 197the short link between 101 at Fort Dick and 199 on the Smith River
SR 299Arcata east through Blue Lake and over Berry Summit, as far as the Trinity County line
SR 255Arcata out to Manila and Samoa and over the Samoa Bridge into Eureka — the peninsula’s only road
SR 211101 at Fernbridge into Ferndale — Ferndale’s only road
SR 36101 at Alton east through Bridgeville, as far as the Trinity County line
SR 254the Avenue of the Giants, Sylvandale to Pepperwood

The six state routes joined the tile on 18 September 2026. Until then it read 101 and 199 only, because the only geography to hand was the feed itself — a night’s closures — and a box drawn round those would have found a closure only where one had already been seen. Each route is now bounded by Caltrans’ own line work for it, cut at our county lines: 299 and 36 stop at the Trinity County line, so a closure at Buckhorn Summit or east of Bridgeville is not on this tile. For the whole length of either, and for chain controls anywhere, use QuickMap.

Roads that are not the state’s are in no Caltrans feed at all. Mattole Road at Petrolia and Shelter Cove Road are county roads: when one of those is out, the tile will show an open 101 and nothing else, and the county is who knows — Humboldt County Public Works, or Del Norte’s.

This tile is not a warning system, and it is not everything. It repeats planned and approved roadwork. A crash, a slide or a tree down an hour ago is not in it, and an empty tile never means the road is clear — only that no approved closure is on it.

Planned work, not tonight’s crash

Caltrans runs a Lane Closure System. It publishes the closures that have been approved for the coming week and reissues the whole list every few minutes, free and without a key. That list is what the tile reads.

So it answers “will 101 be one-way at Klamath tomorrow morning”. It does not answer “why is 101 stopped right now”. Unplanned things — a collision, a slide, a vehicle fire — are the California Highway Patrol’s, and they appear on the CHP traffic incident page while they are happening. The tile does not read that, so when the road is shut and the tile is quiet, CHP is where to look.

Four words, and only one of them shuts the road

Every entry Caltrans publishes carries one of four descriptions. They are not degrees of the same thing: three of them mean the road is open and you will wait.

Caltrans saysOn the ground
Fullthe road is shut. On 101 or 199 that is a long way round, or no way round at all.
One-Way Trafficone lane, both directions, a flagger or a signal. The road is open. You wait.
Alternating Lanesthe same idea where there are more lanes to give and take.
Lanea lane or a shoulder is out. Usually you will not notice.

Only Full closes the road on this board, and only when the crew is actually on scene. Caltrans states the wait itself for the others, in minutes, and the tile prints that number rather than inventing one.

Why the work says it started in March

Long-running control is normal here in a way it is not on flatter coasts. Emergency work after a slide, a bridge being rebuilt a half at a time, a wall going in above the road — these run for months, and a one-way signal can stand on the same mile of 101 or 199 for a year.

The tile says how long, because “one-way since May” is a different fact from “one-way since this morning”. The first is a thing to allow twenty minutes for. The second is news.

Postmiles, not mile markers

California measures each route by postmile, counted from the county line and starting again at every county, which is why 101 runs to postmile 100-odd in Humboldt and then restarts in Del Norte. The little white paddle at the roadside is a postmile marker, and the number on it is the one Caltrans is quoting.

A letter in front of it — R, T, M — belongs to the number and is not a typo. It marks a stretch that was realigned, so the mileage still runs in order. The tile keeps the letter for that reason.

County roads are a different office entirely

Caltrans looks after the state highways and nothing else. Mattole Road, Shelter Cove Road, Bald Hills Road, the roads out to the Lost Coast — every one of those belongs to a county, none of them is in the feed, and none of them will ever appear on this tile.

They close, though, and in winter they close often.

If a county road matters to your day, neither this board nor Caltrans is the place to look. Ring the county.

Chains

Caltrans publishes chain requirements, and this tile does not read them. On this coast they are rare and inland — 299 over the mountains, 36 east of Bridgeville — and they can appear in a few hours. Before a winter drive inland, check QuickMap or ring the highway line.

If you are about to drive it

And if the road you are asking about is Last Chance Grade — the stretch of 101 between Crescent City and Klamath that everybody here asks about — it is a state highway, so when work or a slide closes it, it will be on this tile and on QuickMap both.

Where this comes from

All California guides