Avalanche does not use the same pricing mechanism as Ethereum does. Ethereum uses its consistent block times along with the gas per block as the indicator to set the BaseFee. In Avalanche that idea doesn’t make sense Avalanche allows asynchronous block issuance (there is not necessarily a consistent block time). So Avalanche uses the amount of gas used over time to calculate the modifications to the BaseFee. Essentially - while there is still space in the blocks being issued, there is no space in the time window they were issued in.
If you are a developer and would like to learn more about dynamic fees, click here.