I would try some overcooked rice and boiled chicken or lean ground beef (drained well). Try feeding this only for 24 hours, multiple small meals rather than 2 regular feedings. Slowly begin adding small amounts of kibble over the next few days, reducing the amount of rice and meat mixture accordingly. You can also add a tablespoon of plain pumpkin, (not pie filling!), once or twice a day. Be careful not to overdo the pumpkin as it can work opposite of what you want! Hopefully in a week you will be back to regular kibble meals. If this does not work I would ask the vet to treat for giardia, it can sometimes not show up on testing. If you do treat make sure you do a full 14 day course of meds. You can also try some "Tylan" to help firm up her stools but this will only be a temporary fix as it will not treat any issues that may be brewing.
I hope your baby is feeling better soon, I hate when they are sick! I have never heard of snow causing this and my 2 have eaten plenty!