Validation loss exploding

My validation loss is exploding for some reason. I am working on Kaggle Salt Segmentation challenge. I have heard this issue from one two others as well. My loss decreases but validation just explodes. I also don’t understand how dice shows above 1.

Here is the link to the notebook: https://github.com/bluesky314/Salt-Segmentation/blob/master/salt_segmentation%20(new%20api).ipynb [go straight to cell 65]