Month: June 2021

Red Flag warning extended westward

URGENT - FIRE WEATHER MESSAGE
National Weather Service Medford OR
1103 PM PDT Wed Jun 23 2021

...Scattered Thunderstorms Expected over Northern California
Thursday Afternoon and Evening...

.The low will move southward Thursday focusing scattered
thunderstorm activity over Northern California. Signals are a bit
mixed in the models, with some models hitting the Modoc area harder
than Siskiyou County and others doing the opposite. We expect
thunderstorms on Thursday to begin early and then end earlier than
normal.

CAZ280>282-284-285-250000-
/O.CON.KMFR.FW.W.0011.210624T1900Z-210625T0200Z/
Western Klamath National Forest-
Central Siskiyou County Including Shasta Valley-Shasta-
Trinity National Forest in Siskiyou County-
Siskiyou County from the Cascade Mountains East and South to Mt
Shasta-Modoc County Except for the Surprise Valley-
1103 PM PDT Wed Jun 23 2021

...RED FLAG WARNING REMAINS IN EFFECT FROM NOON TO 7 PM PDT
THURSDAY FOR ABUNDANT LIGHTNING ON DRY FUELS FOR FIRE WEATHER
ZONES 280...281...282...284 AND 285...

* Impacts:  Lightning and high fire danger will likely result in
new fire starts. Gusty thunderstorm winds could contribute to fire
spread. Despite rainfall, initial attack resources could be
overwhelmed and holdover fires are possible.

* Affected area:
 In Northern CA...Fire Weather Zones 280...281...282...284 and 285,
this includes the the Klamath National Forest, Marble Mountains,
Scott Bar Mountains, Shasta National Forest, Modoc National Forest,
Lava Beds National Monument and the communities of Happy Camp,
Seiad Valley, Etna, Fort Jones, Weed, Mt. Shasta City, Tennant,
Canby, Alturas, and Willow Ranch..

* Wind: Gusty, quickly shifting outflow wind gusts up to 40 mph
  range are possible.

* Thunderstorms: Scattered thunderstorms are expected. Isolated
dry thunderstorms are also possible, but most are likely to
produce at least some rainfall.

* Additional Information: Thunderstorms Thursday are expected to
move generally from east to west.

Red Flag Warning Shasta and Plumas Counties:

Red Flag warning June 24th for lightning: “Highest coverage and strongest storms look to be over eastern Shasta county and Plumas county, especially the area between
Burney and Quincy. Main concern with the storms will be abundant lightning, which may start a few fires, especially over foothill locations where fuels are drier and little to no rain falls. A red flag warning has been issued for much of Shasta county,
stretching southeast through eastern Tehama and Plumas county including Mineral, Chester and Quincy through 9pm tonight.”

Fire Weather Watch Thursday Night: Abundant Lightning

URGENT - FIRE WEATHER MESSAGE
National Weather Service Medford OR
319 AM PDT Wed Jun 23 2021

...Abundant Lightning Expected This Afternoon and Evening...

...Scattered Thunderstorms Possible over Northern California
Thursday Afternoon and Evening...

.Low pressure centered southwest of the area will send a series of
disturbances into the area from the southeast. Scattered
thunderstorms on dry fuels are expected over much of western
Siskiyou County and along the Siskiyou mountains in fire weather
zones 280 and 621, as well as the Cascades in northern zone 623,
and northern and central portions of zones 624 and 625. Isolated
storms will be expected over a wider portion of Southern Oregon and
Northern California. While most storms will produce wetting
rainfall, significant lightning on dry fuels is expected.
Scattered thunderstorms are possible again Thursday, but should
remain confined to northern California.

CAZ281-282-284-285-240000-
/O.NEW.KMFR.FW.A.0009.210624T2100Z-210625T0600Z/
Central Siskiyou County Including Shasta Valley-Shasta-
Trinity National Forest in Siskiyou County-
Siskiyou County from the Cascade Mountains East and South to Mt
Shasta-Modoc County Except for the Surprise Valley-
319 AM PDT Wed Jun 23 2021

...FIRE WEATHER WATCH IN EFFECT FROM THURSDAY AFTERNOON THROUGH
THURSDAY EVENING FOR ABUNDANT LIGHTNING ON DRY FUELS FOR FIRE
WEATHER ZONES 281...282...284 AND 285...

The National Weather Service in Medford has issued a Fire Weather
Watch...which is in effect from Thursday afternoon through
Thursday evening.

* Impacts: Lightning and high fire danger will likely result in
  new fire starts. Gusty thunderstorm winds could contribute to
  fire spread. Despite rainfall, initial attack resources could be
  overwhelmed and holdover fires are possible.

* Affected area:
  In Northern CA...Fire Weather Zones 281...282...284 and 285,
  including portions of the Klamath, Modoc, and Shasta National
  Forests, Lava Beds National Monument, and the communities of
  Weed, Mount Shasta City, McCloud, Tennant, Tionesta, Day,
  Canby, and Likely.

* Wind: Gusty and erratic wind gusts to 40 mph are possible in and
  near any thunderstorms.

* Thunderstorms: Scattered thunderstorms are possible. Isolated
  dry thunderstorms are also possible, but most are likely to
  produce at least some rainfall.

* View the hazard area in detail at:
  https://www.wrh.noaa.gov/mfr/HAZARD

Lightning strikes continue in Modoc County and north of there as record heat wave approaches

Daniel Swain@Weather_West·

Another active lightning day across far NorCal & much of southern Oregon. This is not good news, from wildfire perspective, considering prevalence of severe to extreme drought in this region and prospect of historic, long-duration heatwave beginning this weekend. #CAwx#ORwx

Wildfires and climate change push low-elevation forests across a critical climate threshold for tree regeneration

https://pubmed.ncbi.nlm.nih.gov/30858310/

Wildfires and climate change push low-elevation forests across a critical climate threshold for tree regeneration

Kimberley T Davis 1, Solomon Z Dobrowski 2, Philip E Higuera 3, Zachary A Holden 4, Thomas T Veblen 5, Monica T Rother 5 6, Sean A Parks 7, Anna Sala 8, Marco P Maneta 9Affiliations expand

Free PMC article

Abstract

Climate change is increasing fire activity in the western United States, which has the potential to accelerate climate-induced shifts in vegetation communities. Wildfire can catalyze vegetation change by killing adult trees that could otherwise persist in climate conditions no longer suitable for seedling establishment and survival. Recently documented declines in postfire conifer recruitment in the western United States may be an example of this phenomenon. However, the role of annual climate variation and its interaction with long-term climate trends in driving these changes is poorly resolved. Here we examine the relationship between annual climate and postfire tree regeneration of two dominant, low-elevation conifers (ponderosa pine and Douglas-fir) using annually resolved establishment dates from 2,935 destructively sampled trees from 33 wildfires across four regions in the western United States. We show that regeneration had a nonlinear response to annual climate conditions, with distinct thresholds for recruitment based on vapor pressure deficit, soil moisture, and maximum surface temperature. At dry sites across our study region, seasonal to annual climate conditions over the past 20 years have crossed these thresholds, such that conditions have become increasingly unsuitable for regeneration. High fire severity and low seed availability further reduced the probability of postfire regeneration. Together, our results demonstrate that climate change combined with high severity fire is leading to increasingly fewer opportunities for seedlings to establish after wildfires and may lead to ecosystem transitions in low-elevation ponderosa pine and Douglas-fir forests across the western United States.