Saturday, October 31, 2015

Winter Weather Returns to the Sierra


Winter Weather Returns

Our first winter storm of the season with significant amounts of rainfall and Sierra snowfall is poised to affect Northeast California and Western Nevada Sunday into Monday.   A Winter Weather Advisory has been issued for Sunday Evening into Monday for portions of the Sierra from the Tahoe Basin down to Mono County. (areas in the purple shading)


Link to view this map here


Incoming Moisture
This storm system will usher in a solid band of moisture off the Pacific Ocean and will provide healthy rainfall and high elevation snowfall totals to the region. The animation below shows a model depiction of this moisture band (orange and yellow shading).  


This will also coincide with the expected precipitation timing. Rainfall enters northern Lassen County Sunday morning then drops across the Tahoe Basin Sunday Evening and finally Mono County Monday morning. 

Rainfall & Snow Level:
An important note to take away from this storm: Snow levels will be high to start and the bulk of the precipitation will fall as rain. Only areas above 9,000 feet will see all snowfall from the start. 

Snow levels will crash to near 6,000 feet by Monday morning but the bulk of the moisture will have already passed. Monday morning will be the best time frame to see some snowfall at lower elevations but we are mainly looking at just a few inches at most at lake level. You can see the approximate snow level drop on the graphics below. (Can be found here, then click "Snow Level Forecasts")




Rainfall Amounts:
Heaviest rains near and south of the I-80 corridor.
  • Sierra Crest:  2 to 2.5 inches.  (liquid equivalent)
  • Tahoe Basin & areas west of U.S. 395:   1.0 to 1.5 inches
  • Western Nevada: 0.25 to 0.75+ inches. 



Snowfall Amounts:

Tahoe Basin
  • Above 8,500':    1+ feet
  • around 7,000':   3 to 5 inches (including Echo and Donner Summits)
  • Lake Level:        Generally less than 2 inches


Mono County
  • Sierra Crest above 9,000':    1 to 2 feet
  • around 7,000':   3 to 5 inches 


Impacts
  • Travel: As this is the first solid storm of the season, many may not be prepared for winter driving conditions. The highest Sierra passes (Tioga, Sonora, Carson, Mt. Rose) will see the heavier amounts of snow (1+ feet) with Echo/Donner summits seeing a few inches. 
  • Winds: Moderate, possibly blowing around Halloween decorations left unsecured. 
  • Cold: Tue-Thurs with widespread freezes each night. The coldest mornings are expected to be Wednesday and Thursday.

For additional forecast details see our Area Forecast Discussion








Thursday, October 8, 2015

Welcome Tim Bardsley to the NWS Reno Team

NWS Reno is happy to announce that Tim Bardsley recently arrived as the new Senior Service Hydrologist (SSH). As SSH, Tim is the primary NWS contact for hydrologic decision support, forecast and warning services in Nevada and the eastern Sierra.  

SSH Tim Bardsley enjoying the great outdoors.
Tim first became interested in hydrology as a college student while exploring the rivers, mountains and canyons of the West. His undergraduate degree in civil/environmental engineering (University of Colorado at Boulder) and Master’s in hydrology (University of Nevada at Reno) give him a solid framework for hydrologic research. As a researcher at Niwot Ridge, CO, and as a hydrologist at the NRCS Utah Snow Survey Office, he conducted numerous hydrologic investigations as well as repairs and maintenance at well over one hundred hydrometeorological sites in four states, including extensive field work throughout Nevada and the Sierra Nevada.  

Tim's latest position was the Utah Liaison and Research Integration Specialist for the Western Water Assessment applied research program. While in this position, he was stationed at the NWS Colorado Basin River Forecast Center (CBRFC) in SLC, UT.  Among numerous other projects to support resource managers faced with climate variability and change, he used the NOAA Community Hydrologic Prediction System (CHPS) to model the potential impacts of climate change on local and regional water supplies.  He also convened workshops and networked with stakeholders to assess water supply system vulnerabilities and adaptive strategies to improve resilience in the face of climate change and variability.

What is the role of a Service Hydrologist?

There are 124 NWS Weather Forecast Offices and most employ a Service Hydrologist (SH). The SH is responsible for supporting all hydrology operations within a NWS Forecast Office Hydrologic Service Area (HSA). Hydrology operations includes collecting daily observations, monitoring river stages, and issuing river flood warnings or statements when needed.  The Senior Service Hydrologist (SSH) is responsible for more than one HSA.  

Other duties of a SH include:
  • Support development and application of the Community Hydrologic Prediction System (CHPS).
  • Utilize technical skills in information technology and data processing to improve hydrometeorological operations.
  • Conduct and facilitate research and develop training resources for the evolution of the NWS Hydrology Program.
  • Perform simulation testing and provide decision support.
Interested in a NWS Hydrology Position?

A useful reference for learning about NWS hydrology positions and qualification requirements is the NWS JetStream Online School for Weather and all NWS job opening are posted to The Federal Government Jobs Site



Friday, October 2, 2015

Guest Post: Nevada Bureau of Mines and Geology; Nevada's Great 1915 Earthquake

Enjoy this post put together with information from Nevada Bureau of Mines and Geology about the 1915 Pleasant Valley, Nevada Earthquake on its 100th anniversary. All information was taken from The 1915 Pleasant Valley, Nevada Earthquake website.
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When folks talk about earthquakes most people consider California to be earthquake country, but Nevada gets its fair share of seismic activity too! Northern Nevada was very active geologically during 1914 and 1915, as you can see on this short video which shows activity from 1850-2012. Magnitude 6 and 6.4 earthquakes occurred in Reno during February and April of 1914 and Mt. Lassen had several eruptions between May 1914 and October 1915, occasionally dusting Winnemucca with fine ash.   


The Pleasant Valley earthquake of October 2, 1915 was the largest earthquake in Nevada's recorded history. The 1915 Pleasant Valley earthquake was preceded by a rare, highly energetic foreshock sequence that forecasted the ensuing large earthquake. For a detailed description of the sequence check out the October 5, 1915 Silver State Newspaper to read L. Roylance's account of the seismic activity. The mainshock occurred at 10:54pm. Shaking lasted for 40 to 55 seconds over a large area of northern Nevada. Nearly continuous aftershocks created continuous ground motion in Kennedy for at least 15 minutes after the mainshock! It ruptured the ground about 50 miles south of Winnemucca, and left a scar along the range front that was more than 35 miles long. In places, the ground surface was offset vertically by as much as 19 feet. 


The earthquake had a magnitude of 7.3 and was felt throughout Nevada as shown on the Modified Mercalli Intensity Map. The most devastating effects of the earthquake were to buildings on ranches in Pleasant Valley where total and partial collapses devastated some homes and barns. Although the 1915 earthquake took place in a rural setting with only a half a dozen ranches in Pleasant Valley, 100% of the people in the Valley were severely impacted by the earthquake. 

Modified Mercalli Intensity Map of 1915 earthquake. Areas with Intensity VIII to X had partially and totally collapsed buildings, surface rupture from fault movement, and ground cracking. Areas with Intensity VII had shaking strong enough to damage chimneys, within Intensity VI areas walls were cracked, and shaking in Intensity V areas was strong enough to awaken people. 
Winnemucca was the Nevada community with the most earthquake damage. Several brick and adobe buildings in this area had portions of walls thrown down and some plate-glass windows were broken. Damaged chimneys and building contents occurred throughout Winnemucca. For more detailed information check out The 1915 Pleasant Valley, Nevada Earthquake Centennial website.



On the centennial of the October 2, 1915 Pleasant Valley, Nevada earthquake, it is wise to reflect back on this event so that we can be prepared for future earthquakes. Here are some of the important lessons from this large earthquake:

Earthquake Country: The 1915 earthquake underscores beyond a doubt that Nevada is earthquake country and that Nevadans should be earthquake ready. Drop, Cover, and Hold On. Twenty-three earthquakes of magnitude 6 or greater have occurred in Nevada since 1857.

Widespread Damage: The Pleasant Valley earthquake caused damage to multiple communities that were as much as 50 miles away. This illustrates that large earthquakes cause widespread damage and can affect many communities at the same time. It is important for emergency managers to be mindful of these possible effects when planning for earthquakes and considering potential available resources.

Foreshock Activity: The 1915 earthquake had an extraordinary foreshock sequence, including earthquakes of magnitude 5.0 and 6.1. Foreshocks are earthquakes that precede a mainshock. Although usually less energetic, foreshock activity has preceded most magnitude 6 and greater historical earthquakes in the state, making Nevada an excellent area to conduct foreshock studies and experimental earthquake forecasts.

Foreshocks as Early Warnings: Foreshocks associated with the 1915 earthquake could have triggered a useful earthquake warning. Post-earthquake warnings, such as a statement that over the next 72 hours there is an elevated chance of having an earthquake of equivalent magnitude or larger, can be used to initiate temporary mitigation measures and alert emergency responders. As a natural reaction to the 1915 foreshocks, the Pearce family in Pleasant Valley removed the horses from a barn that collapsed during the mainshock.

Building Damage: Building damage from the 1915 earthquake is similar to what might be expected from strong earthquakes occurring today in Nevada. Seismically vulnerable buildings, like unreinforced masonry buildings, commonly have the most damage and have high earthquake risk.


Great Nevada ShakeOut

Join millions of people worldwide practice Drop, Cover and Hold On during Nevada's largest earthquake drill! Register at http://shakeout.org/Nevada/