I thought this was an excellent demonstration of why you can’t always trust the elevation reading on your Garmin Edge. Because the elevation is recorded using the barometric pressure the weather can do some strange things at times.
This is a comparison of two rides 24 hours apart on a 40k course. So what happened? Firstly I should say the blue course is the correct elevation. On the second ride a severe weather front hit while I was out riding. I’m guessing as the front passed over the pressure dropped which would account for the sudden and unexpected rise at the 25k. Well that’s my theory at least, happy to be corrected on this. But at any rate the change in the elevation is curious.