Hey AUB - exposure is essential to be comfortable with before flash use.
I wasn't even sure it was snow in shot 1 it's so dark, but because it IS snow the underexposure makes PERFECT sense.
I recommend manual mode for learning exposure. All camera meters are stoopid in the same way. They average out every scene (based on 18% grey) 100% of the time.

This scene is NOT normal - meaning there is NOT an even representation of tones. When there is an even representation the camera does a good job averaging....but when there isn't, the camera is brainless so it still averages out the scene and feeds you an exposure based on that average. Your job/goal as the photographer is to OVER-RIDE scenes that are not normal. manual mode is best until this becomes second nature.

Bright snow means the camera is averaging it out - and averaging out that much bright snow makes the scene grey.
Solution - increase exposure by at least 2 full stops.
The board's image may be a bit darker because it's 275k max and maybe the image on screen is 20 megs....but the main issue here is the initial exposure....and the flash will not help the entire image only the foreground. This is seen in post 3 where the images are better lit because of the added flash, but the scene overall is still underexposed.

Hope that helps - marko