Thursday's heavy rains and flash flood warning were especially alarming to one discrete population: this year's Honolulu Marathon field.

The winter showers came a year and two days after similarly foul weather contributed to what has been called the largest timing malfunction in the history of the marathon.

At last year's 35th anniversary race, failures in a newly introduced timing system administered by Michigan-based SAI Timing and Tracking resulted in only 1,798 of the 22,839 official finishers receiving accurate finish times. More than 3,070 runners were "lost" by the system.

The National Weather Service predicts partly sunny skies and scattered showers for tomorrow's race.

But even if the weather takes a turn for the rainier, Honolulu Marathon participants won't have to worry about a repeat fiasco, according to Steve Foster, co-owner of Pacific Sports Events and Timing, which has been contracted to provide timing services based on the widely used ChampionChip technology.

First introduced in 1993 and used by the marathon from 2000 to 2006, the ChampionChip is the most widely used timing system in the world for road races.

The system involves a half-dollar-sized plastic disc containing a microchip transponder that transmits the runner's information to a central repository via timing mats placed at designated points along the route.

"All of the components are completely sealed so you could pour water over it and none of it would get in," Foster said. "They're entirely self-contained."

Each component of the system is also equipped with an independent, internal battery, which eliminates the possibility of stray voltage affecting its performance, Foster said.

The technology's long track record includes the 2000 Los Angeles Marathon, in which several timing mats (used to record each runner's time as he or she passes designated points along the route) were completely submerged yet still produced accurate timing information.

The Honolulu Marathon used the ChampionChip before switching to the less cumbersome and potentially cheaper SAI chip last year.

The exact reasons for last year's timing errors have been disputed. Initial speculation by SAI co-founder David Simms focused on a generator that short-circuited before the race due to the heavy rain. Simms said the crash caused electronic readers to reset incorrectly.

Later speculation centered on the possibility that the small microchip-implanted tags that runners attached to their shoes were either improperly fastened or rendered inoperative by puddles and rain during the race.

However, there was evidence that the system had failed before. Official results from last year's Las Vegas Marathon, which also used the SAI system, showed missing split times for hundreds of runners. There have also been online discussion groups devoted to finishers' complaints about SAI timing at both the Las Vegas and Philadelphia marathons.

To ensure that each runner received an accurate finishing time, the Honolulu Marathon Association undertook the unprecedented step of painstakingly examining video footage of the event. The process took an estimated 1,200 to 1,500 man hours at a cost of roughly $50,000.

In October, the Honolulu Marathon Association filed suit against SAI to recover $30,000 that SAI had earlier agreed to pay in compensation for the mishap.