Tire warning

So after we get 20 miles into the mountains, Sally starts sending low pressure warnings for the rear wheel. Hmmm. The the yellow warning eventually turns to a red fault. Sheesh. 

I pull over. Should I ride back to HoM? 

So I too out my trusty compressor (yes, I bought it for this trip), and filled the tire. 

Sorry the pix is sideways. I filled both tires as the bit seemed low. 

The punch line is that HoM just has a crappy gauge. When I filled them to the right pressure, they stayed filled. Whew.