20w09a: World fails to load; tick took 60.00 seconds

This morning the server crashed with the attached crash report, then subsequently failed to load the world. (The maximum tick time is exceeded upon load, and I can not enter any commands on the server console.)

When I try to restart the server, it fails with:

[23:50:28] [Server Watchdog/FATAL]: A single server tick took 60.00 seconds (should be max 0.05)

I copied the world files to a different system and tried again, and was able to reproduce the problem. I then tried attaching the world files, but (even after bzip2 compression) they're too large.

137M snapshot.tar.bz2

Let me know if it would help to send these over some other way.