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<br /> <br />Q. What criteria do }'OU use for determinin~ whether a community <br />or area should have a lIash~flood warning s}'stem? <br /> <br />A. Until recently, we have simply worked with localities that have <br />experienced bad flooding in the past. Since the Camille flooding in <br />Virginia, however, we hav~ designated some of our experts in the <br />field to work actively on the problem of making surveys before a <br />flood makes the need obvious. <br /> <br />Q. How much of a job would it be to make slIch an analysis for the <br />entire country? <br /> <br />A. It would be a huge task, There would be a tremendous number <br />of specific situations to analyze; and those situations are constantly <br />changing, But the idea is being explored now. <br /> <br />Q. Would this take in all the potential disaster areas, including those <br />like Buffalo Creek, where a rupture in a dam was the prime cause of <br />the flash flood? <br /> <br />A. Possibly. But small dams, made of earth or coal-mine waste, as <br />that one was, are a special.category. They are more of an engineering <br />problem-making sure the dams will hold-than a hydrometeoro~ <br /> <br />An experimental radar system produces <br />numerical values for the strength of <br />echoes, which can then be correlated <br />wifh rainfall intensity. (Left) An artist's <br />conception of the digitized display, <br />superimposed on a satellite photograph. <br /> <br />logical problem, involving weather. Rainfall \vasn't the big factor <br />there; it was the dam itself, A related aspect is political-regulations <br />to keep people from living in areas where there is a known flood <br />hazard. <br /> <br />Q. That's a big prohlem in southern California. isn't it? Overbuild. <br />ing in areas ~'here mud slides from heav}' rains are a recurrent threat? <br /> <br />A. Yes. Every year that goes by, more and more California homes <br />are built on steep slopes subject to sloughing off of the soil whenever <br />there are heavy rains. Better warnings won't solve that problem. <br />There is evidence that people are aware of the hazard, yet they con- <br />tinue to take the risk. Efforts to deal with it by better zoning aren't <br />having much success. <br /> <br />Q. Is this a problem. ~enerally-people building or buying homes <br />in areas of high flood.risk? <br /> <br />A. Yes, it is. <br /> <br />Q. How about the conscientious home bu}'cr, \,"'ho wants to avoid <br />flood danger? How can he find out, in ad,'ancc, if a home he's in. <br />terested in is a bad risk? <br /> <br />A. Usually the city or county engineer, or their counterpart will <br />be able to provide the flood history for the area. Or he might check <br />with the local newspaper. There will be articles on file telling about <br />serious floods of the past. <br /> <br />Q. Are Go\'Crnment a~encies doing an).thing to curb this trend to- <br />ward over-building in flood-prone areas? <br /> <br />A. Yes, they are. Under the Federal flood-insurance program, <br />which of course is highly subsidized, part of the requirement for <br />putting the program into effect is that the states will develop zoning <br />systems to keep people from building in flood~prone places. The law <br />requires a delineation of flood-hazard areas, so the situation should <br />take a turn for the better as the flood-insurance program begins to <br />make itself felt. In areas where a flood risk exists but is within per- <br />missible limits for habitation, mortgage companies will insist that <br />home buyers buy flood insurance, adding to the cost of the homes, <br />This, too, will act as a deterrent. <br /> <br />Q. Looking back on the historical record, how did people die in <br />flash floods? "'hat did they do wrong, or neglect to do? And how <br />many deaths were apparently una\'oidahle, with existing limitations <br />on technology? <br /> <br />A. \-Vell, we still have to face the fact that there are certain types of <br />situations right now where even our most sophisticated systems for <br />detecting and issuing warnings for flash floods won't do the job com- <br />pletely. Examples are the Rapid City flooding and the Camille flood~ <br />ing in Virginia, which began when many people were asleep. Un- <br />less we can arrange for some sort of automatic alarm system right <br />inside the homes of persons living in vulnerable areas, they may not <br />be aware of a problem because they won't be monitoring their radio <br />or TV. Not until we get a reliable home~alarm system-perhaps one <br />where we can automatically turn on your radio or TV when there is <br />a warning to be announced-will that problem be solved. <br />Moving then from this extreme category-where people are <br />doomed unless warned immediately that they must leave their homes <br />