Float is created when a Reserve Bank credits a bank for depositing a check but has not yet collected funds from the bank upon which the check is drawn.  Both banks now list the funds on their books.  As a result, both banks have use of the same funds for a short period of time.

Anything that slows the check clearing process can cause float.  Examples include backlogs of checks received over weekends, higher seasonal volume during the holidays in December and January, and delays due to poor weather while transporting checks.  To reduce the amount of float in the check clearing process, the Federal Reserve has used imaging technology.