My first LSC fellow shift, and it didn't disappoint.

Arrived at 8am PST with IFO coming up to ~78 Mpc. Quiet running until a couple of ETMY DAC saturations. The GPS times of saturations are:
1131299869
1131301016
My understanding is that this is a frequently observed glitch, but the mechanism is not well understood.

After LLO lost lock, Chris was doing some opportunistic injections requested by the CW group. Unfortunately, not all of the injections were completed when H1 lost lock.

During the next lock stretch, while there were no observed ETMY DAC saturations, an unfortunate oscillation developed at 13:48 PST (21:48 UTC), observed strongly in H1:ISI-ETMX_ST1_CPS_X_LOCATION and also observed in H1:ASC-DHARD_Y_OUTMON/H1:ASC-DHARD_P_OUTMON. This continued for several minutes, looked to be settling down, but then increased to the point that we decided to try a test increase on the DHARD gain (we took H1 out of observing mode before this test). This was unsuccessful and H1 fell out of lock.

Following the lock loss, H1:ISI-ETMX_ST1_CPS_X_LOCATION continued to oscillate for ~10 more minutes before suddenly settling down without input from the operator. Investigations are ongoing by local site experts.

H1 has now resumed operating at ~78 Mpc.