In compiling our notes for this year, we wanted to give everyone a chance to weigh-in on any flooding events that may have impacted your communities or you personally. As most of you already know, 2020 had very few rainstorms capable of causing serious flood impacts making this year our least impactful since the F2P2 began 42 years ago.
To help with your recall, here are the storm dates that likely produced daily rainfall amounts of 2” or more:
LOCATION(s) POTENTIALLY IMPACTED
General widespread, low intensity rainfall
max GARR >3.29”, no rain alarms
Arapaho, Boulder, Denver, Douglas & Jefferson Counties including Aurora and Lakewood
max GARR >2.97”, greatest number of rain alarms for a single day in 2020
Intense rainfall exceeding 3 inch-per-hour rates occurred on other days , but total rainfall for those days was under 2 inches. For 2020 rainfall intensity/duration/frequency measurements, download the PeakRain Excel workbook.
Any information you can send us will be most appreciated. Thank you for all you do to keep your communities safe.
Final closing climate trivia…2020 was Colorado’s 3rd driest year on record.
Kevin Stewart, P.E. Engineering Services Manager MILE HIGH FLOOD DISTRICT 2480 W. 26th Ave Suite 156-B | Denver, Colorado 80211 Office: 303-455-6277 |Direct: 303-749-5417 |www.mhfd.org Protecting People, Property, and our Environment
Twitter users may want to follow this. We are trying to keep the information simple to limit public confusion.
Automated tweets will be county-specific. Additional hashtags like #flood, #cowx, #rain may be added. If you are a Twitter user, you can start following this now. Simply search for udfcd-fwp. When heavy rainfall is detected by the ALERT System, you should receive something like: Heavy rainfall occurring in ___(blank)___ County.
This text will be following by a link that points you to a “light” version of the ALERT GMap with very limited control features that looks like something this… http://t.co/MnVGlHjrdh. Gmap-LT will show the measured rainfall amounts for the last 3 hours, a transparent looping radar overlay, and the current NWS warning polygons that link to the corresponding NWS warning text. The rainfall measurement that triggered the tweet will blink (see demo).
We recently improved one of our Esri ArcGIS Online maps that you may find useful. The new map shows flood hazard areas, September 2013 flood peaks and hydrography for major drainageways within UDFCD. Stream names can be displayed by clicking on the streams. A link can be found on our ALERT System website from the Maps menu.
A number of changes have been made this past month to improve the performance of the ALERT Map and timeliness of the XML files that are used by other real-time applications.
A second NovaStar-5 server is now fully operational. This backup server mirrors the primary server database at Diamond Hill, is remotely located, and will failover automatically should the primary server become disabled. The backup unit also permits load sharing of data processing task. This means that XML files accessible from cloud services can be updated more frequently. Currently all rainfall, water level and weather data files are updated every minute.
The ALERT Map is one application that benefits from the dual-server implementation. Users should note more reliable automatic 1-minute data refresh rates.
Other changes to the ALERT Map include:
NWS warning area polygons are turned on by default and provide one-click access to the corresponding NWS warning product. Just click on the icon attached to the polygon to read the NWS warning.
WDT looped Radar images are turned on by default reflecting the last hour of activity. All Radar images have their opacity set for 50%, allowing users to easily see the base map. All gaging station readouts overlay on top of the Radar images.
Color coding is applied to all ALERT stage and discharge readouts to reflect threat conditions. The colors correspond to NWS AHPS threat levels with the exception of the blue readout, which represents bankfull conditions.
USGS and DWR streamgage readouts are displayed on the stage and discharge maps using darker green backgrounds to distinguish their data from the ALERT data. Links to corresponding webpages supported by the USGS and Colorado DWR can be found by clicking on the readout.
Time series plots and links to tabular data are available for all ALERT readouts including measured water levels, discharge estimates and rainfall.
We hope you find these improvements useful. As always, your comments and suggestions are welcome.
We have migrated our alert5.udfcd.org URL to a new homepage. This site contains many of the same features available on the previous ‘alert5’ website. We believe you will find this new page much easier to use, especially those of you who have smartphones, tablets and iPads. For those who prefer the previous website, convenient links are provided for accessing the old alert5 webpage.
We have created a snowpack webpage for our new handheld-friendly ALERT System website that contains links to a few of my favorite pages. We hope you find this useful. Let us know if you have other favorites that you would like us to include.
[Fraug 5/16/2014] Monitoring streamflow and water levels
We recently updated a number of ALERT webpages with AHPS features. AHPS is a NWS acronym that stands for Advanced Hydrologic Prediction Service. See http://water.weather.gov/ahps2/index.php?wfo=bou for more information about AHPS. The legend provided was acquired from the NWS AHPS website. The yellow “Near Flood Stage” is also commonly referred to as the “Action Stage.”
Our AHPS-like ALERT webpages use the same AHPS reference levels. These levels are used by NWS as guidance for issuing flood advisories and warnings. Three UDFCD webpages that currently employ this feature are:
[Fraug 4/28/2014] September 2013 Peak Flow Estimates
We are putting together a webmap tool to view peak flow estimates from the floods of last September. Thought you all might be interested in this. Your comments are always welcome. This is a work in progress.