That's the speed plot of Jill's ride so far. It definitely indicates some bike pushing and slow conditions. It appears things got slow right around Flathorn Lake. The Race Update indicates there is drifting snow in open areas (like an open lake!) on top of the freshly fallen stuff.
She rolled into the first checkpoint, Yentna Station, at about 2:40am according to the SPOT (the leaderboard has not been updated with an official time). By contrast, last year she made Yentna by 9pm -- about six hours slower! I'm sure she's taking it all in stride, and remember that last year trail conditions in the first portion of the race were just about ideal, so slower is expected.
I haven't yet seen indication that Jill, Geoff or Billy have progressed beyond Yentna yet. I'll keep watching.