Table of Contents
What is the probability of a 500 year flood?
1 in 500 chance
The “500-year flood” corresponds to an AEP of 0.2-percent, which means a flood of that size or greater has a 0.2-percent chance (or 1 in 500 chance) of occurring in a given year.
When was the big flood in Boulder?
From Sept. 11 through 15, 2013, the Front Range region experienced significant rainfall, causing flooding, loss of life, and widespread damage. More than 18 inches of rain fell in the area causing 25 to 100- year flooding along Boulder’s 15 drainageways.
What year was the 500 year flood?
The US appears to be getting hit with major storms with unusual frequency. From August 2015 to August 2016, there were eight 500-year flood events recorded by the National Weather Service.
What does above the 500 year flood level mean?
A 500-YEAR FLOODPLAIN (0.2% Annual Chance Floodplain) is considered to have a MODERATE flood risk. It is an area that is expected to be inundated by a 500-Year Flood, a flood event having a 0.2% chance of being equaled or exceeded in any given year. The 500-Year Flood is also referred to as a 0.2% Annual Chance Flood.
Which is worse 100-year flood or 500 year flood?
500-year Floodplain, area of minimal flood hazard. 100-year Floodplain, areas with a 1% annual chance of flooding. Because detailed analyses are not performed for such areas; no depths or base flood elevations are shown within these zones.
What caused Boulder flood?
Starting on September 11, 2013, a slow-moving cold front stalled over Colorado, clashing with warm humid monsoonal air from the south. This resulted in heavy rain and catastrophic flooding along Colorado’s Front Range from Colorado Springs north to Fort Collins. The situation intensified on September 11 and 12.
What does FEMA X500 mean?
FEMA Zone X500 Definition/Description: Areas of 500-year flood; areas of 100-year flood with average depths of less than 1 foot or with drainage areas less than 1 square mile; and areas protected by levees from 100-year flood. An area inundated by 0.2% annual chance flooding.
Was Harvey a 500 year flood?
Harvey caused catastrophic flooding in some 500-year zones and many residents most likely did not have flood insurance since it was not required. The same problem also exists in the Special Flood Hazard Area (or 100-year flood zone) where floods happen much more frequently in certain areas.
Is X500 a FEMA Special Flood Hazard Area?
Flood zone X, also known as flood zone X500, is arguably the safest flood zone designation, as it’s considered to be outside the 500-year floodplain and is also protected by a flood control system, such as a levee or dam, from the 100-year floodplain.
How many people died in the Boulder flood?
2013 Colorado floods
| Disaster emergencies were declared by the governor in 14 counties (highlighted) in Colorado. | |
|---|---|
| Date | September 9, 2013 – Early 2014 |
| Location | Colorado, primarily the Front Range, El Paso County and Boulder County, as well as portions of metro Denver |
| Deaths | 8 dead, 6 missing |
What is X500 zone?
When will the Boulder Creek floodplain maps be available?
The Boulder Creek floodplain mapping became effective on December 7, 2017. The floodplain maps were developed based on: Updated topographic data, Updated floodplain, floodway and high-hazard zone boundaries, and
How many CFS is a 500-year flood?
12,000 cfs 500-year 21,800 cfs Stay Connected with Project Updates Email Leave this field blank Related Documents Boulder Creek Restoration Master Plan 2015 pdf Related Projects Comprehensive Flood and Stormwater Master Plan South Boulder Creek Flood Mitigation Fourmile Canyon Creek Flood Mitigation
What is a 100-year floodplain?
One of the areas shown on a FIRM is a Special Flood Hazard Area (SFHA), or the 100-year floodplain. This area has a 1% or greater chance of flooding in any given year.
Where is South Boulder Creek flood mitigation located?
South Boulder Creek Flood Mitigation Fourmile Canyon Creek Flood Mitigation Goose Creek and Twomile Canyon Creek Flood Mitigation Footer menu Calendar Locations Services News Government Accessibility 1777 Broadway Boulder, CO80302 Contact Us Social Media YouTube Twitter Facebook Instagram LinkedIn Nextdoor © 2022 City of Boulder.