While H1 was standing down this evening waiting for the high winds to quiet down before relocking, Jeff and Jenne made the observation that the ground motion we usually see in the 30-100mHz frequency band of the ETM ISI BLRMS from wind was also bleeding into the higher frequency bands, visible up through the 30Hz band. See attachment #1 for wind speeds, attachment #2 for the 30-300mHz bands, and attachment #3 for the 3-30Hz bands.
At first, this behavior was thought to be unphysical, but then Jeff pointed out the ASD of the BRS "super-sensor," where tilt motion is subtracted out (attachment #5, ETMX used as an example). It can be seen that the ground motion is such that the "BRS RY OUT" trace is elevated from the low frequency to above 1Hz compared to the same traces from a day ago (attachment #4), showing that this indeed is the result of strong winds tilting the end stations.
Yes, the winds do tilt the buildings, and if the sensor is above the rotation center then you get a translation. The real model must be more complex because the slab is bending - so there is not a single "rotation center".
In any case, the translation has been seen for a long time. See, for example some of my data and some of Robert's data shown on page 16 and 17 of https://dcc.ligo.org/LIGO-G1501371.
Note - we built a wind fence instead of using the inside/outside sensors. This was a good choice, even though it took a while...