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[concentra]tions that had been uncovered by prior reconnaissance. At times the weather gave an additional aid to the enemy by channelling helicopters into certain flight paths to go underneath the clouds. The enemy, of course, adjusted his fire to the obvious approaches.
The list of ammunition, weapons, and equipment that was destroyed in Operation DELAWARE was most impressive in itself. This was, in a manner of speaking, the enemy's Cam Ranh Bay. However, I believe one of the greatest intangible results of this operation was the psychological blow to the enemy in discovering that there was no place in Vietnam where he could really establish a secure sanctuary. The enemy had always considered A Shau Valley to be his personal real estate and it was a symbol of his relative invulnerability. Operation DELAWARE destroyed that symbol.
From the allied point of view, Operation DELAWARE brought out one important consideration. Weather had been the key planning factor on the timing of this operation from the beginning. The urgency to terminate Operation PEGASUS in order to go into the A Shau Valley was based on inches of rain to be expected after the month of April, not ceilings and visibilities which would prove so critical. In other words, the forecast monsoon rains (which did occur) never produced the terrible flying conditions of low ceilings and scud which preceded them in April. An air cavalry division can operate in and around the scattered monsoon storms and cope with the occasional heavy cloudbursts far better than it can operate in extremely low ceilings and fog. The monsoon rains did, in fact, wash out the hastily constructed airfield but our capability for airmobile operations improved during the period. The lesson learned, then, was that one must be very careful to pick the proper weather indices in selecting an appropriate time for an airmobile operation. An inch of rain that falls in thirty minutes is not nearly as important as a tenth of an inch which falls as a light mist over 24 hours. According to the long range forecast based on old French records, April was supposed to have been the best month for weather in the A Shau Valley. As it turned out, May would have been a far better month—but you don't win them all.