The opinion of the court was delivered by: Ramirez, P. J.
Opinion certified for partial publication.*fn1
This case involves a dispute regarding defendant Southern California Edison Company's (SCE) responsibility for damages sustained by the various plaintiffs as a result of a wildfire, commonly known as the Mill Creek fire, which broke out on October 27, 1993. The fire was alleged to have resulted from a failure in SCE's overhead power line equipment. After a bifurcated jury trial, judgments were entered on June 20, 1997, in favor of plaintiffs Virgil and Alice Barham (the Barhams) on their causes of action for negligence, nuisance and trespass in the amount of $400,500, and in favor of plaintiffs GTE California Incorporated (GTE) and California Department of Forestry and Fire Protection (CDF), on their causes of action for negligence in the amounts of $193,804 and $295,637, respectively. SCE appeals each of the judgments entered claiming several grounds of error. As to all three judgments, SCE asserts five errors in evidentiary rulings, a cumulative prejudicial effect requiring reversal, a lack of substantial evidence to support the liability verdict, and an error in a jury instruction alleged to have combined theories of negligence and negligence per se. In addition to the above, as to the Barhams' judgment SCE asserts an error in a jury instruction on the proper measure of damages and an error in awarding postjudgment interest. Also, as to GTE, SCE claims error in the awarding of prejudgment and postjudgment interest. Finally, as to CDF, SCE claims error in the awarding of prejudgment interest. We find each of SCE's assertions of error to be without merit and therefore affirm the judgments.
On October 7, 1997, the court amended the Barhams' judgment nunc pro tunc to reflect judgment in favor of SCE on the Barhams' cause of action for inverse condemnation. The Barhams appeal, claiming they were entitled to prevail on their cause of action for inverse condemnation.*fn2 We agree and reverse the Barhams' judgment as to that cause of action.
At approximately 6:37 on the morning of October 27, 1993, strong Santa Ana wind conditions caused a section of SCE's 12,000-volt (12kv) power line to break. That uninsulated line momentarily contacted an uninsulated 33,000-volt (33kv) line suspended above it, sending 33kv of power down the 12kv line. When that extra voltage hit a 15,000-volt-rated lightning arrester (AR-182) on a pole three-quarters of a mile away, the arrester failed, causing superheated components to fall to the ground, igniting a brush fire. Richard Cale, a meteorologist, estimated that at the time the fire broke out, the wind speeds averaged 21 miles per hour with 37-mile-per-hour gusts 10 feet above the ground, and averaged 30 miles per hour with 44-mile-per-hour gusts 45 feet above the ground.
Paul Woodruff, traveling down Highway 38 in San Bernardino County, arrived near the subject pole very soon after the fire ignited. At that time the wind was beginning to blow flames across the road. Shortly after his arrival he noted there was vegetation burning in a ten-foot-long triangular area which came as close as three or four feet from the subject pole. There was a clearing of vegetation around the pole, but there was some vegetation within the clearing area, which was burning. The flames were being blown down the canyon to the southwest, away from the pole. Mr. Woodruff never saw vegetation burning to the north of the subject pole.
Kurt Hayden, a heavy equipment operator employed by the United States Forest Service at the Mill Creek ranger station, also responded to the scene of the fire shortly after it broke out. When he arrived, he determined the fire appeared to have come from the area at the bottom of the pole. An area within 3 to 4 feet from the base of the pole still had hot ash and smoke in it but the flames had moved some 70 feet to 50 yards from the pole. While he was in the area of the pole, he observed a "backburn" phenomenon, where the flames burned back from their starting point into the wind instead of with it, to the northeast of the pole. That area had not yet begun burning when he first arrived at the scene.
Bruce Brown, a fire investigator, was assigned by his employer, the CDF, to investigate the cause and origin of the Mill Creek fire. He was directed by Don Buyak of the United States Forest Service to the location where the fire was believed to have started, in the vicinity of the subject pole. Mr. Brown prepared an investigation report, which he later admitted had some discrepancies with times, as well as other problems. He also admitted he had not previously investigated any wildland fires where high voltage electrical transmission facilities were involved and did not know what a lightning arrester was or what the internal components of one looked like. He noticed some damage at the top of the subject pole and some debris on the ground within a 10-foot area around the pole that appeared to have once been an insulator. He also saw some burn patterns within this 10-foot area, some 12 to 20 inches from the pole. He visually examined the burn indicators within a 15-foot radius of the pole and concluded the fire had begun within the 10-foot clearance area. His examination also revealed the presence of a backburn phenomenon to the north of the pole.
Oscar Burrell, Chief of the Fire Prevention Bureau of the CDF in Santa Cruz, was assigned to assist Mr. Brown in his investigation. In attempting to confirm or disprove Mr. Brown's conclusions, he also visited the scene around the subject pole, performed an investigation and prepared a report of his findings. While he was investigating, he found pieces of the lightning arrester both within and outside the 10-foot radius of the pole. He also concluded that the area of origin of the fire was within the 10-foot radius of the subject pole and that the burn to the north of the pole was a backburn.
Klaus Radtke, a resource scientist, reconstructed the fuels which were available within the 10-foot radius of the pole on the day of the fire, as well as the fire start and fire spread. He observed flammable plant materials and evidence of burned vegetation within the 10-foot radius of the pole in the postfire photographs. He also opined the most likely place the fire began was near a bush within the 10-foot radius of the pole.
SCE hired a landscape contractor to remove vegetation to mineral earth in a 10-foot radius under certain of its power poles, including the subject pole, for fire prevention purposes. This removal was to occur one time per year. In 1993, the subject pole was cleared on March 11. The contractor was not surprised at the level of vegetation which had regrown in the clearance zone by the time of the fire.
Joseph Osterhout, an electrical engineer who specializes in lightning arresters, has observed many kinds of staged over-voltage situations to test lightning arresters. Typically, when arresters "fail" due to over-voltage, the superheated internal components fall below where the arrester is mounted, while the porcelain shell pieces are projected outward. In his opinion, while the internal silicon carbide blocks would retain enough heat to ignite a fire after falling from the pole, the porcelain pieces are far less likely to have done so. Absent the action of other forces upon the silicon carbide blocks, generally they would fall to the ground below where they were housed in the arrester, approximately four feet northwest of the pole. Mr. Osterhout did not attempt to perform any calculations with respect to the effect the prevailing winds would have had on the falling silicon carbide blocks.
Lester Hendrickson, a metallurgic engineer and physicist, attempted to determine the probable cause of the subject fire, including the likely trajectories of objects falling from the position of the failed lightning arrester. In his opinion, absent any forces on them, the silicon carbide blocks would have dropped straight down out of the arrester. However, because of the action of the wind on them, they would have moved from 3.25 to 7.42 feet from the spot where they began to fall, depending on wind velocity. He also analyzed the heat retention characteristics of the components of the arrester and determined the silicon carbide blocks would have been the most likely elements to have ignited brush after falling from the pole.
T. C. Cheng, a professor of electrical engineering, testified the silicon carbide blocks would have been propelled out to the southeast when the arrester broke and would not have landed within the 10-foot radius of the pole. Charles Hickey, an SCE investigator with experience investigating failed lightning arresters, testified in some instances, the arrester blows up and the silicon carbide blocks are propelled as far as 40 feet. He could not recall ever having ...