All of this brought heavy pressure on the hurricane hunters and forecasters to be more accurate in the warnings, to “pinpoint” the area to be seriously affected, and to defer the hoist of the black-centered red hurricane flags until those responsible were reasonably sure of the path the storm would take across the coast line. Thus, the warnings actually became more precise, but in some instances the time available for protective action was correspondingly reduced. Precautionary measures must be carefully planned. The force of the wind on a surface placed squarely across the flow of air increases roughly with the square of the wind speed. For this reason, it is a good approximation to say that an eighty-mile wind is four times as destructive as a forty-mile wind. A 120-mile wind is nine times as destructive. In order to lessen property damage, residents of Florida and other states in the hurricane belt prepared wooden frames which could be quickly nailed over windows and other glassed openings. These devices proved to be very effective. In some cases it was a dramatic fact that, if two houses were located side by side, the one with protective covers on windows and other openings escaped serious damage while the other house soon lost a window pane and then the roof went off as powerful gusts built up strong pressures within the building. At the same time that this protection was applied on the windward side, openings on the leeward side (away from the wind) helped to reduce any pressures that built up in the interior. As these experiences became common after 1930, wood and metal awnings were manufactured so that they could be lowered quickly into position to protect windows of residences. Business houses stocked wooden frames that could be fastened in place quickly to prevent wholesale damage to plate glass windows. Many other measures were taken hastily when the emergency warnings were sent out. One, for example, was a check by home owners to make sure that they had tools and timbers ready to brace doors and windows from the inside if they began to give way under the terrific force of hurricane gusts. They had learned that with a wind averaging eighty miles an hour, say, the gusts are likely to go as high as 120 miles an hour and it is in these brief violent blasts, so characteristic of the hurricane, that the major part of the wind damage occurs. In addition, the experienced citizen prepares for hours when water, lights, and electric refrigeration will fail. He knows, too, that these storms have a central region, or eye, where it is calm or nearly so, and he does not make the often-fatal mistake of assuming that the storm is over when the calm suddenly succeeds the roaring gales. He wisely remains indoors and closes the openings on the other side of the house, for the first great gusts will come from a direction nearly opposite that of the most violent winds which preceded the center.