California Code, Government Code - GOV § 25502.7

Notwithstanding the provisions of Sections 25502.3 and 25502.5, the board of supervisors may, whenever it has proclaimed a local emergency pursuant to Section 8630, direct the purchasing agent to engage independent contractors to perform services related to the local emergency for the county and officers thereof, with or without the furnishing of materials, within the amounts the board of supervisors may establish.

The board of supervisors may establish rules and regulations to effectuate the purposes of this section.  Those rules and regulations shall include provisions for informal bidding procedures to the extent that such procedures are feasible under emergency circumstances.