The Torrents in Torrance

At The Guardian, Representative Mike Honda – a seven-term congressman representing the 17th district of California and a member of the House Appropriations Committee, the Safe Climate Caucus, and the Sustainable Energy and Environment Coalition – has co-authored an article about how "we can't let climate change turn droughts, flash floods and mudslides into the new normal."

The first sentence of Rep. Honda's article reads as follows:

Between power outages, deluging rains, flash floods, mudslides and record droughts, California is quickly becoming unrecognizable – all the bellwethers of an ecosystem out of whack.

Of course...because California has never had power outages, deluging rains, flash floods, and mudslides before?  This is all consistent with the concerted efforts of the political left – and of their allies in the scientific establishment – over the past few years to redefine normal weather variability as somehow "weird."

Rep. Honda's statement above regarding flash floods cites this December 16 piece from Southern California Public Radio about how the storm on this day "brings flash flooding to Los Angeles County [and] cars stranded in Torrance."  The story makes no mention of climate change.  So how does this single storm in Torrance from December 16 become a bellwether of an "ecosystem out of whack" due to anthropogenic climate change?

At the NOAA-NWS climate station in Torrance, only 1.10 inches of rain fell on the 16th, less than fell only a few days before on the 12th (1.55 inches) and only slightly more than fell on the 2nd (0.95 inches).  Of course, the intensity of the rainfall is as important as the total depth when considering flash flooding.  But still, the rainfall in Torrance was hardly some biblical event.

The NOAA-NWS Los Angeles Twitter account sent out a tweet on the 16th that there was "[h]eavy rain around Vandenberg AFB. Hourly rate of .62 [inches.] Flood advisory in effect for Santa Barbara County. #LArain."

Another NOAA-NWS tweet from L.A. that day read, "weather spotter in Torrance had 2.34 [inches] of rain in about 2 to 2 1/2 hours with storms over the area late today. #LArain #LAWeather"

There were other NWS tweets regarding the rain intensity in Torrance at the time of flash flooding:

For perspective, the 1-in-100 year one hour storm duration rainfall rate for Los Angeles is 2.1 inches per hour.  According to the U.S. Department of Commerce technical report on "Rainfall Intensities for Local Drainage Design in the United States," a 1-in-10 year one hour storm rainfall rate for L.A. is 1 inch per hour, and the 1-in-10 year ten minute storm rainfall rate is 2.6 inches per hour.  A similar design guidance technical report from the Dept. of Commerce (i.e., the "Rainfall frequency atlas of the United States") comes to analogous conclusions.

In short, this storm in Torrance was anything but historically anomalous, nor was it a bellwether of an ecosystem out of whack.  In fact, it appears to be the type of storm you would expect to see in this area every few years.

The record for one-day precipitation during December in Torrance (which also happens to be the annual one-day precipitation record for the site) is 3.61 inches in 2004, followed closely by 3.47 inches in 1965.  Tuesday's one inch of rain was nowhere near these values.  There are no signs of a significant trend in maximum one-day rainfall amounts for Torrance, nor for the general L.A. area, in December or on an annual basis since records began.

For downtown L.A., these records date back to the 1870s, and the correlation is toward lower maximum one-day rainfall amounts (both in December and annually), not higher.  That seems to be far from an "ecosystem out of whack."

Even a basic knowledge of L.A.'s history indicates that the area is prone to flash flooding – like many other arid regions (see, e.g., much of the American Southwest – which the City of Angels resides within).  As the Curating Los Angeles website correctly notes:

During mild, dry winters such as the one we're experiencing this year [the article was written in March 2012], it's easy to forget that the Los Angeles basin has seen its share of extreme flooding. In fact, intense rainfall, flash floods and their associated debris flows are part of the region's normal climatic cycle.

A particularly calamitous example of such a flood took place in late February and early March of 1938. That event that killed scores of people and destroyed railroad lines, bridges, roads, and many buildings throughout Los Angeles, Orange and Riverside Counties. Although some flood control infrastructure was already in place at that time, the extent of the damage and loss of life set the region on a path of channelization that would dramatically alter the physical landscape.

As Kevin Roderick explained in the LA Times, it '... was the first major flood to occur since the population boom of the 1920s and '30s put neighborhoods in the path that storm runoff had followed for eons. Suddenly, the political will appeared to spend millions of dollars on a network of flood control dams and concrete channels that would become the Los Angeles area's definition of a river.'

But for the real shocker, the County of Los Angeles Chief Executive Office (Office of Emergency Management) has a document on its webpage entitled "History of Floods, Mudslides, Debris Flows, Landslides in Los Angeles County Operational Area."  While there is some useful information in this document that nicely contextualizes the long history of intense rain and flooding in the L.A. region, some massive problems appear to exist within it.

Some specific quotes from this L.A. County official document:

July 14, 1886: 24 inches of rain fall in Los Angeles. At the time it was a record, but that short lived record would be surpassed on August 31, 1889 as 61 inches of rain fall in Los Angeles. The 24 inches of rain was a record for the month of July.

August 31, 1889: Los Angeles records its greatest rainfall in a 24-hour period as 61 inches fall. The rain fall was a record for the month of August ...

October 2, 1986: A band of fast moving thunderstorms raced across the Los Angeles basin as 1.50 inches fell in Pasadena along with 3 inches of hail. 1.02 inches rain fell in Los Angeles, at the time a daily record.

So 24 inches (two feet) of rain fell in L.A. on July 14, 1886, followed by another 61 inches of rain (more than five feet) that fell on the city during August 31, 1889, yet only 1.02 inches of rain fell in L.A. on October 2, 1986, which apparently also was a daily record?

How does this nonsense get published?

On July 14, 1886, only 0.24 inches of rain fell on L.A., not 24 inches.  The decimal place matters.  And this was the only rainfall during July 1886, meaning that only 0.24 inches of rain fell on L.A. during the month, not 24 inches.

On August 31, 1889, only 0.61 inches of rain fell on L.A., not 61 inches.  Again – the decimal place matters.  And this was the only rainfall during August 1889, meaning that only 0.61 inches of rain fell on L.A. during the month, not 61 inches.

And apparently only 0.53 inches of rain fell on the city during October 2, 1986, which was nowhere near a daily record.  The daily record for October rainfall in L.A. was set in 1889 at 3.16 inches.  The rain on October 2, 1986 was only tied with three other years as the 24th highest maximum one-day rainfall during the month since records began.  The record one-day rainfall for L.A. during any month was in January 1956 – when 5.71 inches fell.

That 0.53 inches of rain on October 2, 1986 wasn't even the largest one-day rainfall during that year.  In February of 1986, 2.50 inches fell in a single day on L.A., followed by 1.95 inches in a single day during September of that year, 1.61 inches in a single day during March, and so on.  The 24-hour rainfall total on October 2, 1986 wasn't even a major event for that year, never mind all-time in the city.

There are problems all over the place on this topic.  But overall, we can be confident that the rainfall in and around Los Angeles this past week was not an indicator of climate chaos.  Since Rep. Honda appears to hold "a Bachelor's degree in Biological Sciences" and "in his 30-year career as an educator, Honda was a science teacher, a principal at two public schools, a school board member, and he conducted educational research at Stanford University," one hopes he will be more cautious when discussing science.

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