Crypto prices fluctuate, quite dramatically at times, meaning that the ICR that the users start with will fluctuate up and down. In this example, the price of ETH is currently $1,861.60, but in a few hours will decrease by $100. If we do some simple math, we can see that the lower the denominator on debt / collateral gets, the higher the percentage representing the CDP is. The result of increasing a CDP is that it increases your risk of liquidation depending on how close you are to the liquidation rate.