One of the many hazards included in the construction of the transcontinental railroad was snow. Massive amounts of snow from the Sierras eastward to Sacramento created avalanches that often wiped out newly constructed stretches of rail. In 1887 engineers used implemented heavy beams from local timber to construct a sturdy device that not only furthered construction but keep the trains rolling, even today. They're called snow sheds and initially were placed over several miles of exposed track to funnel the sliding snow over the top of the tracks. Today the snow sleds remain a common method for combating the destructive force of avalanches on railroad and highway routes throughout the world. Instead of wood they are constructed with reinforced concrete and steel. On steep slopes, dangerous snow conditions are lessened by installing snow fences that anchor the snow packs. Today marks the 75th anniversary of the Japanese attack on Pearl Harbor. The attack by the Japanese Imperial forces was not deterred by weather however coded covert weather terminology was used to alert oversees officials prior to the attack. When Japanese-Soviet relations were broken the message would read, KITA NO KAZE KUMORI or "North wind, cloudy." If Japanese-British ties were cut, the message would read, NISHI NO KAZE HARE or "West wind, clear" and severing relations with the United States; the message would read, HIGASHINO KAZE AME, or "East wind, rain." The message was broadcast at the end of shortwave radio reports also alerting officials to destroy all sensitive documents.