(AgAlert) - As firefighters in Southern California worked to achieve full containment on the Thomas Fire, agricultural officials in Ventura County issued their first estimate of damage to crops and farm structures, reporting that losses will exceed $171 million, with more than 70,000 acres of cropland and rangeland affected.

The Ventura County agricultural commissioner's office based its initial assessment on information about agricultural locations within the perimeter of the fire, which started on Dec. 4 and grew into the state's largest wildfire, burning nearly 282,000 acres as of late last week.

In a preliminary disaster report to the U.S. Department of Agriculture, Ventura County Agricultural Commissioner Henry Gonzales estimated more than 10,289 acres of irrigated cropland and another 60,000 acres of rangeland in the county had been affected by the fire. He estimated the cost of the damage to current and future crops, machinery and equipment, dwellings, service buildings and other structures at nearly $171.3 million, with avocados and citrus crops suffering the highest losses.