CalClim: California Climate Data Archive

CALIFORNIA CLIMATE WATCH
CURRENT ISSUE: October 2005

Read the full newsletter here: PDF format

Water Year In Review

By Laura Edwards
Western Regional Climate Center

What an exciting last 12 months in California! Water Year 2005, ending September 30, 2005, was quite eventful. Temperature statewide was near normal in all climate divisions, except in the North Coast where it was slightly warmer. Data from the National Climatic Data Center (NCDC) show the last water year to be the coolest of the last 5 years. Precipitation, however, was the dominating story of the year with all climate divisions reporting above average precipitation, with the exception of the North Coast region. The NCDC ranks Water Year 2005 as the 19th wettest since 1895. The U.S. as a whole was also ranked 19th wettest since 1895, but was much warmer, being the 6th warmest water year on record.

Figure 1. La Conchita landslide, January 2005. Photo courtesy of USGS: http://landslides.usgs.gov/recent/current.php

One sign of the changing times is the U.S. Drought Monitor (http://www.drought.unl.edu/dm/monitor.html). According to this weekly frought status map, most of the state began the water year in abnormally dry to moderate drought conditions. By the end of the winter, all but a section along the north/northeastern part of the state was back to no drought status. The exceptional winter storm activity brought most of the in-state reservoirs back up to healthy levels and created a substantial snowpack in the Sierra Nevada, easing the hydrological concerns.

A fairly in-depth discussion of the winter season was presented in the April issue of this newsletter, so will not be detailed here. The winter did bring a lot of National Weather Service Cooperative Stations to near record annual precipitation however, and that trend died quickly last spring. Only a handful of stations, mainly in the north, reported below average precipitation for the water year. Most recorded 100-200% of average annual totals, with the South Coast region averaging even higher, between 200-300% of average. This resulted in weakened slopes, and 2 major landslides occurred in La Conchita in January and Laguna Beach later in the year. FEMA made a disaster declaration for many southern counties after the winter storms ended on January 11th. All of this winter rain wasn't necessarily bad news for everyone. Death Valley had one of the most magnificent spring flower displays in history.

Figure 2, right. National Climatic Data Center California Annual Precipitation.

Hydrology
The Department of Water Resources uses a precipitation index of 8 stations in the Northern Sierra to forecast water availability in the spring, but is monitored throughout the year. This year, the index ended just above the average 50.00 inches at 57.5, or 115% of average. This was also above the 2004 water year total of 47.3". The majority of the precipitation fell in December, with 10.9" reported that month, but May was exceptional with 8.3", or 395% of average for the month, making it the wettest May on record (since 1922). July, August and September were the driest of the year, with 0" precipitation the first two months and 33% of average in September.

The large reservoirs that hold runoff from the 8-Station Index sites also ended the water year on a high note, with more water reserves than last year at the same time. This bodes well for fish because of the ability and need to release water in preparation for storage from the winter season precipitation.

Tornadoes
Water Year 2005 was a very active tornado year in California. By the end of June, there were almost 30 confirmed tornadoes, which made it a record year. There were 8 tornadoes in February alone. Fortunately, nationwide, this spring and summer is in the record books for one of the longest death-free periods from tornadoes.

Figure 3. Flowers in Death Valley, http://pic.templetons.com

Heat Wave
The summer season was relatively mild, with one significant hot streak in the Central Valley in early-mid July that carried over into the Great Basin. A number of 100+ degree days were reported, and Fresno set a record for most consecutive days of 100 or higher.

Page last updated 12/15/05.

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California Climate Watch Archive All data in the Climate Watch is provisional and subject to change. Please contact us for updated and quality-checked data. For 2004 stories, click here For 2005 stories, click here Monthly Weather Summaries 2005 2004	CALIFORNIA CLIMATE WATCH CURRENT ISSUE: October 2005 Read the full newsletter here: PDF format Water Year In Review By Laura Edwards Western Regional Climate Center What an exciting last 12 months in California! Water Year 2005, ending September 30, 2005, was quite eventful. Temperature statewide was near normal in all climate divisions, except in the North Coast where it was slightly warmer. Data from the National Climatic Data Center (NCDC) show the last water year to be the coolest of the last 5 years. Precipitation, however, was the dominating story of the year with all climate divisions reporting above average precipitation, with the exception of the North Coast region. The NCDC ranks Water Year 2005 as the 19th wettest since 1895. The U.S. as a whole was also ranked 19th wettest since 1895, but was much warmer, being the 6th warmest water year on record. Figure 1. La Conchita landslide, January 2005. Photo courtesy of USGS: http://landslides.usgs.gov/recent/current.php One sign of the changing times is the U.S. Drought Monitor (http://www.drought.unl.edu/dm/monitor.html). According to this weekly frought status map, most of the state began the water year in abnormally dry to moderate drought conditions. By the end of the winter, all but a section along the north/northeastern part of the state was back to no drought status. The exceptional winter storm activity brought most of the in-state reservoirs back up to healthy levels and created a substantial snowpack in the Sierra Nevada, easing the hydrological concerns. A fairly in-depth discussion of the winter season was presented in the April issue of this newsletter, so will not be detailed here. The winter did bring a lot of National Weather Service Cooperative Stations to near record annual precipitation however, and that trend died quickly last spring. Only a handful of stations, mainly in the north, reported below average precipitation for the water year. Most recorded 100-200% of average annual totals, with the South Coast region averaging even higher, between 200-300% of average. This resulted in weakened slopes, and 2 major landslides occurred in La Conchita in January and Laguna Beach later in the year. FEMA made a disaster declaration for many southern counties after the winter storms ended on January 11th. All of this winter rain wasn't necessarily bad news for everyone. Death Valley had one of the most magnificent spring flower displays in history. Figure 2, right. National Climatic Data Center California Annual Precipitation. Hydrology The Department of Water Resources uses a precipitation index of 8 stations in the Northern Sierra to forecast water availability in the spring, but is monitored throughout the year. This year, the index ended just above the average 50.00 inches at 57.5, or 115% of average. This was also above the 2004 water year total of 47.3". The majority of the precipitation fell in December, with 10.9" reported that month, but May was exceptional with 8.3", or 395% of average for the month, making it the wettest May on record (since 1922). July, August and September were the driest of the year, with 0" precipitation the first two months and 33% of average in September. The large reservoirs that hold runoff from the 8-Station Index sites also ended the water year on a high note, with more water reserves than last year at the same time. This bodes well for fish because of the ability and need to release water in preparation for storage from the winter season precipitation. Tornadoes Water Year 2005 was a very active tornado year in California. By the end of June, there were almost 30 confirmed tornadoes, which made it a record year. There were 8 tornadoes in February alone. Fortunately, nationwide, this spring and summer is in the record books for one of the longest death-free periods from tornadoes. Figure 3. Flowers in Death Valley, http://pic.templetons.com Heat Wave The summer season was relatively mild, with one significant hot streak in the Central Valley in early-mid July that carried over into the Great Basin. A number of 100+ degree days were reported, and Fresno set a record for most consecutive days of 100 or higher. Page last updated 12/15/05.