Monday, August 12, 2013

Another view of Elephant Butte Reservoir


If you live in New Mexico, follow the news about the drought, and concerned about water supplies you probably have seen a graphic comparing Elephant Butte Reservoir this year with 1994. If you have not viewed this, I urge you to see it on the NASA Earth Observatory webpage. I can't count the number of times someone has emailed this to my inbox.  The number of times it has been emailed brings to attention the importance of this body of water to the region and how it responds to upstream water supply and downstream demand.  Max Bleiweiss, Director of CARSAME, printed a couple of Landsat 8 images of the reservoir about a month apart that I found striking. He compared June 6 and July 8, 2013 on a poster side by side similar to the images below.
Elephant Butte storage on June 6 was 172,470 acre-ft and 60,327 on July 8.  The July date was about the minimum storage for the year after the irrigation. I find it amazing what one month of  about 2000 cubic feet per second flow out of the reservoir can do to the appearance of the lake. Even with a record low irrigation season, you can still a lot of changes.  Since the north end (greenish color) of the reservoir is shallow, most of the changes are seen there. Based on the US Bureau of Reclamation data the difference in surface area between the two dates was 3,190 acres.
 


Thursday, July 25, 2013

Monsoon Storms Causing Issues Across New Mexico

The past two days have been rainy ones in New Mexico. Thunderstorms in the southern and central parts of the state have brought much-needed moisture, and while residents are grateful to see some rain falling, the storms have brought along some nasty side effects.

The CoCoRaHS precipitation map for today shows rainfall amounts recorded throughout the state for the last 24 hours. CoCoRaHS volunteer observers record the amounts present in rain gauges at 7 am (or thereabouts). Many New Mexico residents reported that they experienced the rain and thunderstorms in the evening and throughout the night, times when rain is a little more likely to fall during monsoon season. Notice that only two of the counties with stations sending in reports show no precipitation falling over the last 24 hours (five counties show no stations reporting for the day, as of this morning).

Precipitation amounts for the 24 hours leading up to 7 am on July 25 for New Mexico. Source: cocorahs.org


The precipitation map for July 24, showing precipitation accumulation for the previous 24 hours prior to 7 am on Tuesday, shows rainfall in fewer areas of the state, with the most significant rainfall occurring in the southwestern part of the state.

Precipitation amounts for the 24 hours leading up to 7 am on July 24 for New Mexico. Source: cocorahs.org

News sources have reported on the impacts of thunderstorms that occurred throughout the state yesterday. These reports clearly show some of the weather hazards that can come with the monsoon season. The TV station KRQE out of Albuquerque reported that a car was struck by lightning while driving in Torrance County yesterday; luckily, no one was injured. Last night, many in Dona Ana County experienced a few hours straight of thunder and lightning activity. The map below shows the lightning strike frequency from 6 am on July 24 to 6 am on July 25, 2013. The red and orange colors show the highest frequencies of strikes (greater than 14 and from 8 to 13, respectively). Notice just how much of the state received lightning strikes over the past 24 hours.
Map from the Predictive Services Program. Source: http://psgeodata.fs.fed.us/lightning_frequency.html

New Mexicans do see an increase in lightning and thunder this time of year. In fact, according to a report from NOAA, the region impacted by the Mexican Monsoon sees the most lightning activity in July and August of any area in the Western Hemisphere. And New Mexico has the highest rate of deaths from lightning strikes in the country at nearly two deaths per million people. NOAA has a lightning safety page to help you stay safe during thunderstorms.

The Albuquerque Journal reported that as much as two inches of rain fell in Guadalupe County yesterday and that flooding closed part of a road in Rio Rancho. KFOX 14 TV news out of El Paso reported on flooding in Vado in southern Dona Ana County. They included video of the flooding, showing the water running up to the porch of a trailer home and running in torrents down the street. Families had to be evacuated from their homes in this instance. Flash floods are a chief danger during monsoon season. They can develop and become dangerous very quickly. Today, all of southwestern and parts of central-western and central New Mexico are still under a flash flood watch. See the National Weather Service website for the latest warnings and advisories for your area.

Perhaps the most striking weather event to occur over the last few days was on Tuesday, when a microburst damaged homes and businesses in Columbus, a village in Luna County 30 miles south of Deming. A microburst is a type of downburst, which occurs when a wind rapidly descends from a thunderstorm and spreads out when it impacts the earth; a microburst is a downburst of less then 2.5 miles in diameter. This particular microburst had winds of up to 90 mph and did damage to some 29 structures in the village. No injuries were reported. Downburst winds are one of the leading causes of weather-related damage in the state.

So while you're enjoying the rain that's falling this monsoon season don't forget to be on the lookout for any potential dangers that can come with the thunderstorms, winds and lightning shows.