43 CFR §2091.5-3

1. (a)When the Secretary determines that an emergency exists and extraordinary measures need to be taken to preserve values that would otherwise be lost, a withdrawal is made immediately in accordance with § 2310.5 of this title. Emergency withdrawals are effective on the date the Public Land Order making the withdrawal is signed, and cannot exceed 3 years in duration and may not be extended.
2. (b)The lands covered by an emergency withdrawal are opened automatically on the date of expiration of the withdrawal unless segregation is effected by the publication in the Federal Register of a notice of a withdrawal application or proposal.