Uses of CoCoRaHS Data


Who Uses CoCoRaHS Observations?

YES, IT REALLY IS TRUE!  Your data are used every day!

No matter how many times we repeat this, the question just keeps coming up "who cares about and who uses the observations from CoCoRaHS volunteers?" It must be hard to fathom that precipitation data is so useful and that backyard rain gauges have a place of importance in national and global climate monitoring in the 21st Century.  But the fact is, it’s true. Your rainfall reports -- including your reports of zero precipitation – are very valuable and are being used EVERY DAY. Every morning many organizations pull data from the CoCoRaHS database at least every hour to get all the latest reports as they come in.  They wish all CoCoRaHS observers submitted their reports right away.

When you see forecasts of river stages and flood levels on the Missouri, the Mississippi, the Ohio, the Colorado River or most anywhere else in the country -- guess what data are helping the forecasters make these forecasts? Yes, timely CoCoRaHS data!

Your reports of hail or heavy rain may trigger the NWS to issue severe thunderstorm or flash flood warnings. In cases of extreme localized storms, your local report could help save lives. 

Don’t let all this “importance” frighten you.  The weight is not all on observers shoulders.  The real value comes from having thousands of volunteers reporting from all over.  So keep up the good work, and go out and find more weather enthusiasts to help measure, map and track the amazingly variable patterns of precipitation.

A key reason that CoCoRaHS data are so useful is because the rain gauge used by CoCoRaHS volunteers – the 4-inch diameter, 11.30” capacity clear plastic rain gauge is very good. Under most circumstances, this type of gauge  performs as well as the official National Weather Service Standard Rain Gauge that has been used for over 120 years documenting our nation’s climate.  Most CoCoRaHS volunteers have found representative locations to mount their gauge to get very high quality readings.  The CoCoRaHS gauge, if installed and used properly, provides very accurate readings.  CoCoRaHS volunteers tend to be very interested and very committed to careful and high-quality observations.  As a result, the data are usually excellent for a wide range of uses.

Below are just a few of our many users, there are probably many others.  The most obvious ones that come to mind are:

1. Weather Forecasters
2. Hydrologists
3. Water management
4. Researchers

5. Agriculture

6. Climatologists

7. Insurance Industry
8. Engineering
10. Many others

Thanks for being a CoCoRaHS observer and rest assured that your observation efforts are producing much fruit.

1. Weather Forecasters (Private, Media and Government)

Weather forecasters look at our rain, hail and snow reports to help their weather prediction and verification. Believe it or not, weather forecasters like to know how their forecasts work out. CoCoRaHS precipitation data allow them to see with great detail where it rained or snowed, where it didn't and how much.  Here in Colorado where CoCoRaHS started in 1998, forecasters have learned from CoCoRaHS reports that there are some areas that often get more (less) precipitation than others under certain weather conditions. They have been able to refine their forecasts thanks to these improved detailed local observations.  NOAA's National Weather Service Forecast Offices instantaneously receive our "Significant Weather" and "Hail reports" to aid in severe weather prediction, warning and verification.  This is why CoCoRaHS strongly encourages volunteers to make use of the “Significant Weather” and the “Hail” report forms whenever severe weather is occurring.

2. Hydrologists

CoCoRaHS data is used in hydrologic prediction.   Hydrologists whose job it is to predict stream flows, river levels, reservoir volumes, water supplies and flood potential use all the precipitation data they can get their hands on to try to improve their forecasts. Hydrologists all across the U.S. look at CoCoRaHS data on a regular basis.

Some regular hydrologic users are:

- NOAA’s Weather Prediction Center (WPC) a division of NOAA's National Centers for Environmental Prediction (NCEP)

- NOAA's National Weather Service River Forecast Centers are using CoCoRaHS data every day in predicting river levels and potential flooding all across the country.  A critical input to river stage and flow prediction models is “Mean Areal Precipitation” -- the precipitation averaged across a watershed.  The more rain gauge reports we get, the more accurately NWS RFCs can assess “Mean Areal Precipitation” - and that equates to better forecasts.

- NOAA's National Operational Hydrological Remote Sensing Center (NOHRSC) accesses CoCoRaHS snow reports all winter to help in the assessment of snow cover and snow water content across the U.S. and southern Canada. They particularly appreciate the observers who make the extra effort to report the depth of snow (both old plus new snow on the ground) and the total water content of snow on the ground (snow water equivalent – SWE) in the winter and spring. That is really important stuff.

3. Water management

There are an ever-growing number of municipal water providers and regional water managers who use CoCoRaHS data to help assess available water supplies and current and projected customer demands based on local and regional precipitation patterns.  Daily observations are important in water management, but so is precipitation accumulated over weeks, months and seasons.  CoCoRaHS observations help by providing these seasonal hydrologic panoramas.

4. Researchers

Precipitation has an impact on many parts of nature, commerce and society. More and more scientists in a variety of diverse fields are finding out about CoCoRaHS measurements. Forest pathologists, for example, can sometimes track the spread of certain diseases that propagate best during wet weather. Mountain pine beetles, on the other hand, thrive best during drought. Several scientists and public health officials have used CoCoRaHS day-by-day precipitation patterns to determine where mosquito populations have hatched in order to help track the spread of the West Nile virus.  Mosquito control operations in some parts of the country also use CoCoRaHS precipitation data and maps to determine where and when summer spraying may be needed. CoCoRaHS is used in basic climate research.  One researcher has asked CoCoRaHS volunteers to measure the pH of the rainfall across their state to determine if there is an acidification of their water from upwind industry.  There are many other examples of research applications where observers' data play an important role.

5. Agriculture

Precipitation affects agriculture in so many ways. Farmers, ranchers, agribusinesses and commodities investors all follow weather prediction and national/international rainfall patterns. A few examples include monitoring crop development, crop yield prediction and assessment, diseases, insects, and soil moisture assessments. How much it does and doesn’t rain affects commodities prices and also affects investment and marketing strategies.  Many who are not involved in agriculture may not realize just how much the prices paid to farmers for many commodities vary daily based on observed and predicted weather conditions both here and abroad.  Colorado State University's wheat breeding program uses CoCoRaHS observations to better understand the climate situation of the state and thus develop better wheat varieties for Colorado.

The U.S. Department of Agriculture is looking at CoCoRaHS data regularly to assess crop development, potential drought stress and possible crop damage and erosion from flooding or from drought.

The U.S. Drought Monitor uses CoCoRaHS data in helping to chart drought throughout the country.  Observers reports (especially those zeros) provide an important tool for determining where drought is lurking and to what degree it is affecting the agricultural interests in specific counties.

6. Climatologists

Climatologists have more uses for CoCoRaHS data than you may ever realize. They monitor the development, spread and retreat of drought locally and across the nation.  This requires as many rain gauge reports as possible. This is just one of many reasons why it is important for volunteers to report 0.00” on days with no precipitation as well as rain on snow amounts on stormy days.  Climatologists track the year-by-year variations in precipitation to determine common patterns, long-term averages, probabilities and extremes.  Climatologists look to see if there are areas that regularly receive more precipitation than others -- are there preferred storm tracks and rain shadows? It may take years to prove, but scientists are patient and constantly on the watch for variations and change. They are very interested in the size, intensity and duration of different types of storms. Having many volunteers close together makes it easier to understand the spatial variability of precipitation and how that varies from place to place and with the season of the year.  Also, the more rain gauges there are, the easier it is to spot and correct observation and reporting errors.  Once such group of climatologists using CoCoRaHS data are members of the American Association of State Climatologists (AASC) .

7. Insurance Industry

Insurance claims adjusters have learned about CoCoRaHS as a way to verify if storms were present on days when damage claims were filed.  Use of CoCoRaHS data to helps to prevent fraudulent claims.  CoCoRaHS reports can play a role in hail damage, flood damage, crop losses, traffic accidents, lightning strikes, structural snow load accidents, ice related injuries and other precipitation related claims.  Knowing what fell from the sky, in what area, on a certain date is important information for this industry.

8. Engineering

Did you realize that engineers and architects who design our homes, offices, roads, downspouts, etc. have to take precipitation into account.  Roof drains, slopes and gutter designs are based on rainfall and snowfall data.  Many aspects of building engineering in cold regions of the country are based on the potential weight (load) from accumulated snow and ice.  The design of roads, parking lots, bridges, culverts and storm sewers must all carefully consider the likelihood, magnitude and intensity of heavy rains in order to safely and cost effectively handle flood waters, and much more.  Hail data are used by engineers for developing roofing materials, for building airplanes, for designing roof trusses (based on the heaviest anticipated weight of accumulated hail in the most hail-prone regions of the country).  Your data goes in to helping engineers know the probability for extreme events such as 100-year storms in an area.  This information helps them make the right choices for safety when developing their designs.

9. Recreation

There are many ways that precipitation data are used for recreation applications. Fisherman may check recent rainfall amounts since rain can affect water levels, water clarity and water temperature. Rafters, canoers and kayakers watch for precipitation amounts and for melting snow that will affect water levels. Winter recreation pays close attention to snowfall, snow depth and water content for obvious reasons.  Golf course managers rely on precipitation measurements when determining how much to water their greens.  Some major league ballparks (such as Target Field, home of the Minnesota Twins) have CoCoRaHS gauges to help them know how much rain has fallen on the field.  Precipitation measurements are valuable to both work and play.

10. Many others

There are many others who use CoCoRaHS data on a daily basis.  Below we have listed a few.  Perhaps you can think of more. With each passing year, more organizations are learning about CoCoRaHS data.    This list will keep growing.

Here are some specific examples:

 -- Weather radar correction and calibration: Radar has been used since World War II to track storms. It is a very valuable tool for tracking storm location, movement and intensity.  More recently it has been used to quantitatively estimate the rainfall reaching the ground. It is possible to estimate precipitation amounts from radar, but actual rain gauge observations are critical to this process.  CoCoRaHS reports that arrive promptly each morning and our "Intense Precipitation Reports" are used routinely to help correct and adjust radar precipitation estimates by research scientists, National Weather Service forecasters and private meteorological businesses.

-- The National Drought Mitigation Center (NDMC) looks at CoCoRaHS data each week in the assessment of local and regional drought – and in anticipating areas that may be on the verge of drought.

-- NASA has used our hail data in assessing the risk of hail at Kennedy Space Center.  NASA and NOAA scientists and educators have been using CoCoRaHS data to help validate satellite estimates of rainfall, soil moisture and evapotranspiration.

-- NOAA's National Centers for Environmental Information (NCEI).    CoCoRaHS data have proven to be reliable and of comparable quality to the National Weather Service precipitation data sources.  Therefore, NCEI began including CoCoRaHS daily precipitation data in the Global Historical Climate Network archived data set and can now be accessed through this federal repository for global climate data.

-- The Federal Emergency Management Agency (FEMA) has recently begun to accept CoCoRaHS reports to identify and confirm snowstorms worthy of federal disaster declarations.

-- Fisheries use CoCoRaHS observations (Maine Coastal Waters for example) to determine when there has been large amounts of runoff draining into bays, etc.  This helps them to decide when to close the waters to shellfish harvesting.

-- The media (newspapers, TV stations, internet news services) in many parts of the country use CoCoRaHS data to provide more detail on local storm patterns.

-- Many local utilities look at CoCoRaHS data to help gauge inputs to their water supply and also project water demand.  Snow reports from CoCoRaHS volunteers are of great value since there are very few sources for high quality snowfall, depth and water content measurements from trained observers.

-- Legal applications.    Weather is often a contributing factor to accidents and a variable that may provide useful crime scene evidence.  Increasingly attorneys and law practices are using CoCoRaHS data in forensic investigations.

-- Education.  CoCoRaHS data are used every school day as data that are ideal for classroom analysis, plotting graphs, and connecting weather to its impacts and consequences.

-- Homeowners.  One CoCoRaHS observer tells us "I use CoCoRaHS date to turn off and off my home irrigation system.  I also share data with a friend a mile away to compare."