What mode do you use for shooting pictures? For years I used Auto mode and got crap. Program (P) is much better, especially with the ability to manually adjust the white balance (your new Canon should be able to do that). Auto just does a horrible job with snow conditions and so do special "snow modes" because they assume all snow conditions are the same, which they are not. If you get crap, you should be able to shot in RAW with that new Canon as well... you can often times salvage a crap JPG by working the RAW file, if you want to invest some time in learning how to do that.
Sometimes cameras will have trouble setting exposure properly with all the white snow. You can also see if the camera has an exposure bracketing setting. Then the camera will take three photos when you press the shutter. One with the exposure it thinks is right, one over exposed and one under exposed. I used that setting to take pics in a cave without a flash and it worked pretty well.
Auto just does a horrible job with snow conditions and so do special "snow modes" because they assume all snow conditions are the same, which they are not. If you get crap, you should be able to shot in RAW with that new Canon as well... you can often times salvage a crap JPG by working the RAW file, if you want to invest some time in learning how to do that.
A camera's internal meter takes all the color values of the scene, averages them, and assumes that it will be a 15% gray (exactly between black and white). Shooting an all light-toned scene (beach, snow), it will set the exposure such that the snow and sand should be gray. Beach/Snow mode is an exposure compensation to make it a stop brighter than the camera wants it to be.
Basically, if it's bright/lots of snow, try to look for an exposure compensation setting and put it at +1 (or play with it until you get good results).
Shooting in RAW is awesome for editing in post, but the file is 5x bigger than a JPEG.
I had a day were all my pictures were whiteouts like those. I have a Canon S100 And while it generally takes excellent photos, sometimes it gets a bit fidgety. It's relatively easy to mistakingly change a menu setting. Especially when it's freezing out and you want to get your hand back in the glove as soon as possible.
I'd recommend that you go into the main menu and restore the camera to its default settings. I did that and all the whiteouts went away. P, Is the program mode and allows you to alter more settings then the auto green mode. It's likely that while in the P mode you hit the function button and inadvertently changed a setting.
Another thing to consider is Your focus setting. Many of these cameras do face detection, evaluative, And spot focusing. The exposure is then tied into the focusing Mode you chose. This can lead to unexpected results. Hope you fix it soon. Poindexter and I look forward to your trip reports and they wouldn't be the same without the Excellent photography!