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Phase 1 floods (shown as dark green on map) inundate low areas near the Skagit River, may cover a few small sections of roads, and occur every few years on the average. These floods generally do not cause significant damage in the Skagit River Valley. A large phase 1 flood occurred in December 1989. Phase 2 floods (shown as purple on map) inundate a wider area and may cause significant damage. The large phase 2 flood depicted on this map is approximately what occurred in December 1975 which was estimated to be a 10-year event (a flood that would have a 10% chance of occurring on any given year) Phase 3 floods (shown as orange on map) can cause catastrophic damage in the valley. The very large phase 3 flood depicted on this map is the FEMA mapped 100-year flood. This flood would have approximately a 1% chance of occurring on any given year. If such a flood were to occur, many hundreds of homes would be flooded, thousands of people may have to be evacuated, and numerous public facilities and businesses would be inundated. In some neighborhoods flood waters would be deep and currents swift. Many roads would become impassable and extremely dangerous to use. The 1990 & 1995 floods were smaller phase3 floods. As a result portions of the phase 3 areas were flooded in 1990 and 1995. Caution: Under extreme conditions a flood greater than the 100-year flood can occur. This USGS gage is located near the community of Concrete at river mile 54.1 on the Skagit River. This USGS gage is located at the Riverside bridge on the main stem at river mile 17.0. Note: Gage heigths (measured in feet) indicate level at which the flood phase begins at the gage location. Flood severity may significantly increase as the flood moves from the upstream to the locations. Flood travel time from Concrete gage to Mount Travel times are averages from past floods, actual travel times may vary depending on flood size, storm distribution, and other factors. Phase 1 Phase 2 Phase 3 28.0 32.0 37.0 to to to 32.0 37.0 48.8+ Phase 1 Phase 2 Phase 3 28.0 32.0 35.6 to to to 32.0 35.6 40+ Note 1: The inundation limits shown on this map are for the purposes of flood emergency preparedness only. The flood limits shown are approximate and may not accurately correspond to the actual limits of any given flood due to the unique and complex nature of individual flood events. Note 2: The phase areas on the map represent the areas that are likely to become inundated if the largest floods within each phase occur. Smaller floods within each phase may not inundate all of the phase area indicated. Note 3: Creek flooding usually occurs prior to, and independent of, river flooding. The information on this map will not necessarily help predict creek flooding. Note 4: Photographic evidence was used to map the phase1 and phase 2 floods. Note 5: This map was developed in 1996 by the U.S. Army Corps of Engineers and Skagit County Officials. For further information contact Skagit County Public Works, Surface Water Management Division.