EASTERN SAUDI ARABIA -- An Air Force squadron sent to attack Iraq's Republican Guards returned to its base with a full payload of bombs because heavy clouds had rendered its target invisible.
Intelligence officers say the intensive hunt for Iraqi President Saddam Hussein's mobile Scud launchers has been hampered by fog, which makes it harder for U.S. pilots to spot the truck-mounted launchers as they scuttle away after firing.
And, said Maj. Tim Rush, an F-16A pilot from Columbia, S.C., "We haven't taken out [Iraq's air defense systems] yet due to the weather. I think personally it will take days to weeks."
Weather -- chiefly in the form of clouds and fog -- has suddenly become a significant nemesis in the U.S. and allied war against Iraq. Clouds and fog over Iraq, not unusual during the desert winter, are hampering efforts to identify and destroy Iraqi targets and to assess damage, Pentagon officials say.
"We've had weather problems," Lt. Gen. Thomas W. Kelly, head of operations for the Joint Chiefs of Staff, acknowledged yesterday. "Honest to goodness, we're having problems with it."
Kelly refused to disclose how seriously the weather has hurt the allied air attack. But industry sources say that the clouds and fog make it most difficult to hit key targets that require great precision: mobile "Scud" missiles, sheltered Iraqi aircraft, and military equipment and facilities in residential neighborhoods.
"The rate of damage on the most critical targets is reduced by 50 percent to 75 percent when there's [inclement] weather," said a former combat pilot who helped to develop some of the planes being used in Operation Desert Storm. "All of those are very difficult to hit in bad weather."
Unlike Vietnam, where inclement weather often grounded U.S. pilots for days at a time, allied planes are using new technology to bomb Iraq around the clock, even when targets are covered in clouds. Tornadoes, F-111s, F-15s, F-16s, F-18s and A-6s all operate with radar and inertial navigation systems that enable them to fly at night and under any conditions.
But military experts say that clouds can force pilots to fly dangerously low over targets, rendering them more vulnerable to anti-aircraft fire or accidents. Low visibility also makes massive coordinated air attacks far more treacherous, analysts say.
In addition, rain can limit the effectiveness of lasers and infrared sighting devices by interfering with the transmission of infrared energy through the atmosphere. Assessing the impact of bombing missions has been a particular problem as cloud embankments restrict satellite and aerial photography, Pentagon officials say.
"You want to take out the air defenses before you move on to other targets," said Loren Thompson, deputy director of National Security Studies at Georgetown University. "But before you can verify that those air defenses are out, it would be dangerous to move on to the next target."
Continued inclement conditions will stretch out the duration of the air conflict, experts say. "It's a serious problem in terms of overhead access," Thompson said.
"It will definitely slow down the campaign and make it longer."