MANILA, Philippines — Delta Air Lines Inc. rerouted as many as eight transpolar flights between the U.S. and Asia as the most-powerful solar radiation storm since 2003 hit Earth.

Jets were sent farther south, lengthening trips by about 15 minutes, to avoid potential radio disruptions, Anthony Black, a Delta spokesman, said Wednesday. Air Canada and Qantas Airways Ltd. also shifted the path of some flights, while American Airlines, United Continental Holdings Inc., and Air New Zealand Ltd. said no planes had been rerouted.

Airlines are at risk for a loss of communications on Arctic routes because they use high-frequency radios on flights in the region instead of satellite-based systems, said Doug Biesecker, a solar physicist at the National Oceanic and Atmospheric Administration’s Space Weather Prediction Center. Solar storms can interfere with the radio signals, he said.

“This one is unusual because it’s so strong,” Biesecker said in an interview from Boulder, Colorado. He said it was the 11th-most-powerful storm measured since 1975.

About 8,000 flights a year operate on polar routes, typically between Asia and North America, because they’re the shortest path for many destinations on the two continents, Biesecker said. He said the storm may last until late Thursday New York time.

The blast of energy from the storm can cause fluctuations in Earth’s magnetic field, temporarily affecting navigation, power, satellite and communications systems, according to the space weather center. The storm moved toward Earth at 4 million miles (6.44 million kilometers) per hour, the center said.

Delta may adjust the routes of as many as eight flights a day over the next few days depending on the storm, Black said. Flights between the Atlanta-based airline’s Detroit hub and Hong Kong, Beijing, Seoul and Shanghai may be among those affected, he said.

“We want to ensure we maintain contact and communication with the aircraft by making these adjustments,” Black said.

Qantas will divert its Sydney-Buenos Aires flight Thursday, which typically flies over the Antarctic, and add an extra five tons of fuel to compensate for the longer route.

“We’re not flying as far south as we normally would,” Sophia Connelly, a spokeswoman for Sydney-based Qantas, said by telephone.