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Ultras · US · CA

Doomsday

Half Marathon
Registration open
Registration is open.
Race dateDecember 12, 2026
Start7:30am
Whenin 49 days
First held2023

Who's going to Doomsday?

I'm running itPlan your weeks and your aid station times I'm crewingWhen to leave, where to park, at every stop I'm pacing or cheeringAsk your runner for their Out Here link

Free. You can start with nothing.

Entry Aid stations Notify me if this race changes
Free, and always will be. NavRun makes money from race-day planning for runners who want it, never from this. Ultras change constantly, sometimes the morning of. Always confirm with the race director and the official website before you rely on anything here.
Distance From the name
Half Marathon The race calls this course “Half Marathon” and hasn't published a measured distance. Trail courses often run long.
Climb
not checked yet
Descent
not checked yet
High point
not checked yet
Time limit The race
5:00:00
Aid stations
3
Started
does not apply to this race
Finished
does not apply to this race
Finish rate
not checked yet
The course

Where it goes · 3 aid stations

The Half Marathon starts together with the 50K at the Cool Staging Area in Cool, California, with a single aid station on course and a 5-hour cutoff, generous enough that hikers and trekking poles are welcome.

The race lists the Half Marathon's elevation change as 1,250 feet of gain/loss.

The race

What this one is

Doomsday closes out the year in Cool, California with a 50K or Half Marathon on the trails above the American River Canyon outside Auburn, run every December. The cutoffs are generous, 9.5 hours for the 50K and 5 hours for the Half Marathon, so hikers and trekking poles are welcome on both courses. Every finisher earns a weighted medallion, and the combined field across both distances is capped at 200 runners.

Getting in

Getting in Entry, lottery and what the race asks of you before race day.

Lottery
not checked yet
Lottery opens
not checked yet
Lottery draw
not checked yet
Field cap
200 ultrasignup.com
Registration
UltraSignup ultrasignup.com
Qualifying
not checked yet
Minimum age
not checked yet
Transfers
not checked yet
Deferrals
not checked yet
Crew access, pacers and drop bags

The rules that shape your day Anything marked "not checked yet" is a gap in what we hold, never a no from the race.

Crew allowed
not checked yet
Vehicles per runner
not checked yet
Pacers
not checked yet
Muling
not checked yet
Drop bags
not checked yet
Cupless
not checked yet
Course marking
not checked yet
Night running
not checked yet
Dogs
not checked yet
Headphones
not checked yet
Crew rules
not checked yet
Pacer rules
not checked yet
Drop bag rules
not checked yet
Cutoff philosophy
Doomsday gives the Half Marathon a 5-hour cutoff, generous enough that hikers are welcome and trekking poles are allowed. ultrasignup.com
Aid stations

Every stop, and what you get there ● yes   ○ no   ? nobody has checked   – does not apply to this race

Mile Station Cutoff Crew access Bag Pacer Med To next
0.00 Cool Staging Area
NoneSignal wrong?
 ? ? ? ? ? ?
8.88 Knickerbocker Terror
NoneSignal wrong?
 ? ? ? ? ? ?
? Finish
NoneSignal wrong?
 ? ? ? ? ? ?
Same race, other lines

Other distances and other years

Other distances
50K
What it looks like out there

Somebody has been out there with a camera the tables say the climb is long. these say what long feels like.

Nobody has been out there with a camera or a microphone yet. A gap means nobody has found it, not that it is not out there. Seen a course preview or a film of this one? Send us the link.

Add to this page

What you know every one of these is read by a person before it changes anything

Ran this race? Tell the next runner what you know.

Nobody sees it until we have read it. No account, no sign-in.

Leave blank if it applies to the whole race.

Leave blank if it is not about one particular stop.

Optional. Something like “Cal Street, mile 62 to 78”.

Write it the way you would say it to someone at the start line.

Optional, and it decides nothing. It only tells the next runner where this is coming from.

Optional.

Optional, and never shown on the page. Only so we can ask you a question about this note.

Leave this field blank.

See something wrong or out of date? Suggest an edit.

This changes nothing on the page on its own. Somebody checks it against the race first.

Optional. Filled in for you when you start from a specific line on the page.

Copy it as it appears, so we can find it.

The corrected value.

Required. Where it came from: the race email, the runner manual, what you saw on the day.

Optional.

Optional. A screenshot or a photo of the sign works.

Optional, and it decides nothing.

Optional.

Optional, only so we can come back to you about this correction.

Leave blank if it is about the whole race.

Leave blank if it is not about one particular stop.

Leave this field blank.

Were you out there? Say which stops a text got out from.

Nobody sees it until we have read it. No account, no sign-in.

Optional, and it decides nothing.

Which stops did a text get out from?

Leave a stop blank if you did not try, or do not remember.

50K

  • Cool Staging Area mile 0.0
  • Knickerbocker Terror mile 8.9
  • The Dissent of the Descending mile 13.9
  • No Hands Horror mile 21.2
  • Robie Point Resurrection mile 23.1
  • No Hands Horror mile 27.8
  • Finish

Half Marathon

  • Cool Staging Area mile 0.0
  • Knickerbocker Terror mile 8.9
  • Finish
Optional. Never shown.
Seen a course preview or a film of this one? Send it over.

Somebody watches it before it goes anywhere near this page. What we are after is footage of this course, on the ground. If it would be just as true of any other race, it is not this.

Required. A line is plenty. Where the climbs are, what the footing does, what the last twenty miles look like.

Optional, and it decides nothing.

Optional.

Optional, and never shown on the page. Only so we can ask you a question about this one.

A YouTube link, a race report, a photo gallery, whatever it is.

Optional, and we credit them on the page.

Leave this field blank.

Have the GPX? Send us the link.

We want the address of the file the race publishes, not the file. We download it from there so the page can say where the line came from.

The page or file on the race's own site.

Optional, and only so we can ask you a question about it.

Are you the race director? Get in touch and we'll make it right.

We read every one of these and we write back. Every fact here carries the source it came from, and the way a wrong one gets fixed is a person checking it against what you tell us.

Required, because this is a conversation and we write back.

Tell us what is wrong, out of date, or missing on this page. We read every one of these and we will get back to you.

Optional.

So we know who we are writing back to.

Optional. Director, assistant, comms, whoever you are.

Leave this field blank.

Where this came from. Every fact on this page records its source and when we last checked it: 41 sources for this race. Hover a source link to read the sentence it came from.
20% of what we track for a course is filled in. The rest says "not checked yet" rather than guessing.
See something wrong or out of date? Suggest an edit
Ran this race? Tell the next runner what you know
Were you out there? Say which stops a text got out from
Got footage of this course? Send us the link
Are you the race director? Get in touch and we'll make it right.
Anything else: [email protected]

Ultras change. We will tell you when this one does.

Cutoffs move, races get postponed, lotteries open and close. We read the race's own sources and record where every fact came from. Put your email in and we will send you what changed, and where we read it.

No account, and nothing to cancel.

What happens to your email. Nothing else. I do not sell it, and I will not send you anything except this race changing. One click gets you out.

I keep this catalog because the information is scattered and hard to trust. Telling you when it moves is the same job.

Ultras change. We will tell you when this one does.

Cutoffs move, races get postponed, lotteries open and close. We read the race's own sources and record where every fact came from. Put your email in and we will send you what changed, and where we read it.

No account, and nothing to cancel.

What happens to your email. Nothing else. I do not sell it, and I will not send you anything except this race changing. One click gets you out.

I keep this catalog because the information is scattered and hard to trust. Telling you when it moves is the same job.