Scourge of the Plains: Tornadoes

Ellen Mae stepped out of her two-story home in central Illinois. "Fine morning," she said to herself after checking the weather, and then went back inside. The radio had mentioned a severe storm advisory, but the sky was clear, and it was rather calm. Still, she decided to be safe and kept her radio on.
　　About noon she felt a strange kind of pressure. Looking out her window, she noticed the sky had become overcast. Low, rounded, oddly colored clouds were forming. It was still and oppressive. "Maybe I'd better listen to the weather report again," she murmured to herself.
　　Again the radio forecast severe weather, warning citizens to listen for the siren and seek shelter should a twister, scourge of the plains, come down from the heavens like a "Devil's tail." "I doubt it'll happen over Crossville," she comforted herself. "It always happens in other towns."
　　By two o'clock it started to rain, and the wind picked up, too. The apple tree in front of Ellen Mae's house started to pitch back and forth violently. Her dogs started to bark and howl, and that was when she heard that awful sound.
　　At first she thought it was a locomotive, but she quickly remembered that there was no railroad within 20 miles of her home. She looked into the sky and then noticed it, a dark, swirling mass of black cloud sucking up everything it touched and hurling objects at horrific speeds straight up or straight to the side. Ellen Mae ran as fast as she could down into her storm cellar, a special room which had been prepared by her father when he was still alive. This room was located in the southwestern corner of the basement and had a door with a strong bolt. Ellen Mae ran in, locked the door behind her, and waited.
　　She didn't have long to wait. With shrieking and swooshing sounds right out of hell, the funnel cloud passed directly over her house. An enormous vacuum cleaner, the twister blew the house apart, scattering five generations of Ellen Mae's family belongings over half the rural county she lived in. Within minutes, the winds had stopped, and an eerie silence replaced the cacophony of moments earlier. Feeling it was now safe to venture out, Ellen Mae unbolted the door, peered out, and started to cry. She could look straight up into the sky. Even though she had lost her house and everything in it, she felt lucky. She knew that every year, hundreds of people could perish in tornadoes.
　　Just what are these "devil storms"? They go by many names across the Great Plains of the United States and Canada, not to mention many other countries around the world, but tornadoes are perennial plagues in central North America. The conditions there —— flat land and proximity to cold air masses (from the Rocky Mountains to the west) and warm and humid air masses (from the Gulf of Mexico to the south) provide the optimum breeding ground for tornadoes. According to the U.S. National Weather Service, tornadoes form from thunderclouds and can reach swirling speeds in excess of 600 kilometers per hour. They last from minutes to an hour or more and can blast their way across as much as 150 kilometers of terrain at about 50 kilometers per hour. They vary in width from a few meters to 1,500 meters (average 200 meters). And they strike fear into the hearts of everyone.
　　The safest place to be when a tornado is in one's area is a basement, preferably the southwest corner (where the tornado normally comes from). If driving, track due north or south, as tornadoes usually move from west to east. Weather prediction and tracking these days is far superior to earlier years, but tornadoes can appear without any warning at all, as a large one did right in the heart of Salt Lake City in 1999, leaving a trail of shocked, wounded, and dead as well as pulverized property.
　　Though relatively few people have ever seen a tornado, those who have wish they hadn't. The "Finger of God" is nature's atmospheric fury at its worst.

　　梅艾伦步出她位于伊利诺伊州中部两层楼的家，察看过天气之后，她自言自语说：“美丽的早晨。”然后回到屋里。收音机提到一则有关强烈暴风雨的警讯，但天空清朗无云，一切都相当平静。尽管如此，为了安全起见她还是决定让收音机开着。
　　大约中午时分，她感觉到一股奇怪的气压。从窗口望出去，她看到天空乌云密布，而且一团团颜色怪异的云正在低空形成，空气静止而且沈闷。“也许我最好再收听一下气象报告，”她喃喃自语着。
　　收音机里再度传来恶劣天气的预报，警告市民注意收听警报，万一龙卷风这平原祸害突然像“恶魔的尾巴”一样从天而降时要寻找掩护。“我想不会发生在克罗斯镇吧，”她自我安慰道，“因为每次都是发生在其它镇上。”
　　到了下午两点开始下起雨来，风也变强了。梅艾伦屋前的苹果树开始剧烈地左右摇晃，她的几只狗开始狂吠嚎叫。就在这时，她听到了那个可怕的声音。
　　起初她以为是火车头，但她很快就想到她家附近方圆30多公里内并没有铁路。她向天空一望，然后看到了它——一大团黑压压旋转的乌云将所有碰到的东西都吸了进去，并且以骇人的速度将各种物体直接甩到空中或旁边。梅艾伦飞快地跑进躲暴风雨的地窖，那是她父亲生前设置的一间特殊房间。这个房间位于地下室的西南角落，有一道门闩很坚固的门。梅艾伦跑进去、锁上身后的门然后等待。
　　没等多久，那夹带着尖锐刺耳呼啸声的漏斗云就直接扫过她的房子。龙卷风就像支巨大的吸尘器一样把梅艾伦的房屋吹散，并将她家中传了五代的家产撒落在半个她所居住的乡村小镇上。几分钟之后风停了，一片诡异的宁静代替了片刻之前的喧嚣声。心想现在出去很安全了，梅艾伦打开门闩往外一瞧，然后就开始哭了起来，她抬头就可以直接看到天空。即使失去房子和里面所有的一切，她仍觉得很幸运。她知道每年都可能会有好几百人在龙卷风中丧生。
　　这些“魔鬼暴风”到底是什么呢？它们在美、加大平原中就有许多种名称，更不用说全世界其它许多国家了，只不过在北美中部龙卷风是长期性的祸害。那儿的情况——地势平坦而且又靠近冷气团（来自西边的落基山脉）和湿暖气团（来自南边的墨西哥湾）——提供了龙卷风绝佳的滋生地。根据美国国家气象局的资料，龙卷风是由雷雨云所形成，旋转速度每小时可高达600公里以上。它们持续的时间从几分钟到1小时或更久不等，并且能以50公里左右的时速横扫过150公里之地。它们的宽度从几公尺到1500米都有（平均200米），并将恐惧深植在每个人的心中。
　　龙卷风来袭时最安全的去处是地下室，最好位于西南角落（龙卷风通常从这个方向过来）。如果正在开车，就往正北或正南方向走，因为龙卷风通常由西向东移动。现今的气象预测和追踪远比早期先进，但龙卷风会毫无预警地出现，就像1999年出现在盐湖城市中心的大龙卷风一样，留下一路的惊魂者、伤者和死者以及支离破碎的房屋。
　　虽然曾经见过龙卷风的人相当少，但看过的人都希望他们从未看过。这只“上帝的手指”是自然界大气之怒的终极展现。