Patterson," Troy called as he leaned into his poles and moved out across the newly-crushed snow on the slope.

"Thank you, Dr. Braden," Alec called in his wake, "you may proceed to the patient."

They worked past the buried radiation gauge to the crest and then turned and came slowly back along the wind ridge, following directly behind the detection needle. Troy glanced at his intensity gauge. The needle was on the "danger" line in the red. He stopped. Behind him, Alec checked his drop slowly down the windward side of the slope, reading his own meter. When his intensity needle hit the same mark, he, too, halted about thirty feet to Troy's right.

"I'm dead on," Troy said, indicating with a ski pole an imaginary line straight ahead.

"I've got it about forty-five degrees left," Alec called, marking his position and a direction line in the crust with a pole. Each moved towards the other and from the mid-point of their two markings extended with their eyes the imaginary lines to an intersecting point some thirty feet from Troy's original sighting.

"Hand me the heat tank, doctor," Troy said, turning his back to Alec, "so that we can excavate the patient." Alec unclamped a hand tank and nozzle device from his pack.

With the tank slung under his arm and with nozzle in hand, Troy moved forward another ten feet, gauging the wind velocity. He aimed to the windward of the intersecting lines and triggered the nozzle. A stream of liquid chemical melting agent shot out into the wind and then curved back and cut a hole into the snow. Troy moved the nozzle in a slow arc, making a wide circle in the snow. Then he cut a trough on the downhill side for more than twenty feet. He adjusted the nozzle head and a wider stream sprayed out to fall within the already-melting circle. The concentrated solution was diluted with melting water and spread its action. As the hydrologists watched, the snow melted into a deep hole and the chemically-warmed water torrented down the drain cut to gush out on to the snow slope and quickly refreeze as it emerged into the sub-zero air.

Troy shut off the liquid and the two men waited and watched. "The gauge was recording ninety-seven inches of pack when it quit," Alec said. "Better give 'er another squirt."

Troy fired another spray burst of chemical into the now-deep hole and then widened the drain trough once more.

Then he began spraying a three-foot wide patch from the edge of the hole back towards himself. Immediately a new trough began to form in the snow pack and the water poured off into the hole surrounding the buried gauge.

While the snow was melting, Alec had removed his skis and stuck them upright in the snow. He dropped his pack and unfastened a pair of mountain-climber's ice crampons and lashed them to his ski boots. In five minutes Troy had "burned" a sloping, ice-glazed ramp deep into the snow field, sloping down into a ten-foot deep chasm and terminating on bare wet soil. Sitting on the ground, slightly off center to one side of the original hole was the foot-round gray metal shape of radiation snow gauge P11902-87. A half-inch round tube projected upwards for three inches from the center of the round device.

Alec was down in the ice chasm, ski pole reversed in his hand. Standing as far from the gauge as possible, he dangled a leaden cap from the end of his ski pole over the projecting tube. On the third try, the cap descended over the open end of the tube, effectively shielding the radioactive source material in the gauge. Once the cap was in place, Alec moved up to the gauge and put a lock clamp on the cap and then picked up the gauge and moved back up the ramp.

The wind was screaming across the top of the slot in the snow pack as he pushed the device over the edge and then heaved himself out into the teeth of the storm.

He could barely make out the form of Troy fifty feet east of the original position of the gauge. The tall engineer had taken the replacement gauge from his pack and was positioning it into the snow on the surface of the snow pack. The replacement was bulkier than the defective unit and it was different in design.

This was a combination radiation-sonar measuring gauge. Placed on top of an existing snow field, its sonar system kept account of the snow beneath the gauge to the surface of the soil; the radiation counter metered the fresh snow that fell on it after it was placed in position. The two readings were electronically added and fed into the transducer for automatic transmission.

Troy hollowed out a slight depression in the fresh snow and pressed the gauge into the hollow, then packed the snow back around it to keep it from being shifted by the high velocity winds until fresh snows buried it. Satisfied that it was properly set, he removed the radiation cap lock and slipped his ski pole through the ring on the cap. He backed away, lifted the cap from the gauge and then quickly moved out of the area.

Alec had stowed the bad gauge in his pack and removed a pressure pillow gauge to put into the deep hole in the snow. The man-cut chasm would serve as a partial gauge hole and, from a purely research point of view, it would be interesting to know how much snow would drift and fall back into the hole. The pressure pillow contained a quantity of antifreeze solution and some air space. As the snow fell upon the pillow and piled up, its weight would press down and the pressure upon the pillow would be measured by instruments and again relayed to a small transmitter for reading back at Spokane. The pillows were used in many flat open areas where snow pack was uniform across a large level surface.

The pillow in place, Alec again climbed from the chasm and was locking on his skis when Troy slid up. The ice-dry snow was driving almost horizontally across the face of the ridge and the two engineers had to lean into the force of the wind to keep their balance. Troy fumbled a small service monitor from his parka pocket and shifted it to the new radiation gauge frequency. The signal was steady and strong and its radioactive source beam was hot.

"Now is the time for all good snow surveyors to get the hell outta here," Alec exclaimed as he slipped his ruckpac onto his shoulders. "The gauge O.K.?"

Troy glanced once more at the monitor and nodded. "Hot and clear." He shoved the monitor back into his pocket and grasped his ski poles. "Ready?"

"Let's go," Alec replied.

Turning their backs into the wind, the men veered sharply away from the site of the new gauge and dropped off the crest of the mountain top back to the lee side of the slope. Out of the worst of the wind, they skied easily back down towards the timberline.

Once back among the trees, the visibility again rose although the going was much slower. It would be dark in another two hours and they wanted to be back at the Sno cars with enough light left to pitch camp for the night.

"I heard of a guy over in Washington," Troy said as they worked their way down through the trees, "that won the DivAg award as the most absent-minded engineer of the decade."

"Since you never tell stories on yourself, it couldn't have been you," Alec quipped, "so what happened?"

Troy schussed down an open field in the trees and snowplowed to a slowdown at the opposite side to once again thread through the dense spruce and pine.

"This joker did the same job we just finished," he continued. "He put the new gauge in place while his partner fished the old one out. Then he forgot that he had put the new gauge in place, uncapped mind you, and when they took off he skied right over it."

"Right over the top of it," Alec gasped.

"Yup," Troy said.

"What happened to him?"

"Nothing to speak of. Of course, he's the last of his family tree—genetically speaking, that is."

Fresh snow had completely covered their tracks made during the climb to the summit, but they wouldn't have followed the same trail back down in any case. Both men