California Seasonal Fire Weather/

Fire Danger Outlook

February 2003

Urban Interface and up to 80% tree mortality - Lake Arrowhead area in

Southern California (01/2003)

Executive Summary

This report is a product of the National Seasonal Assessment Workshop held February 24-28, 2003 in Phoenix, Arizona. This workshop brought together experts in the field of climatology, meteorology, fuels and fire danger.

The objective of this report is to assess the factors that will affect wildland fire potential in California during the 2003 wildland fire season. This report is based on past developments, current conditions and trends, and predictions for the next several months. It provides information and recommendations that can improve preparedness for wildland fire management agencies.

Given that this report was generated prior to the significant weather months of March and April, it provides a baseline of information that can be utilized as a preliminary outlook by all California wildland fire agencies. The GACC Predictive Service Units will issue monthly assessments of fire weather and fire danger. An updated version of the Fire Season Outlook will be prepared prior to the start of fire season.

The specific objectives of this report are to:

• State current fire weather and fuels conditions in California.
• Develop fire weather predictions for spring into summer.
• Develop a statement of probable fuel conditions for spring into summer, and identify areas of concern for fuel conditions across the state.
• Develop a prognosis of the wildland fire potential based on available fire weather and fuel predictions.
• Provide a general statement on resource availability of all agencies.

California is expected to have spring season trends in temperature ranging from just below normal in March to at or above normal in May. Spring precipitation should be near to below normal over northern California and slightly above normal in southern California. For the summer period, we expect both temperatures and precipitation to be near normal over northern California, with above normal temperatures and slightly below normal precipitation over southern California. Confidence levels for these weather projections are 70% regarding temperatures and 60% for precipitation.

There are two particular areas of concern regarding fuel conditions in California. One is the drought-affected, large dead fuel moistures east of the Cascade/Sierras in northern California. The second concern is the significant brush dieback and drought/bug-killed timber areas of Southern California. These are likely to cause extreme fire behavior even under moderate fire weather/fire danger conditions.

Indications from the current weather and climate outlook are that fire season will start in the typical time frames across much of California. However, the drier eastside areas will see fire season start earlier, and be of longer duration, than normal. Fire danger is expected to be above average in all parts of the state except the western two-thirds of northern California (see Fire Season Outlook Map on next page).

California Fire Season Outlook 2003

Current Weather Situation

An El Nino pattern developed over the equatorial regions of the Pacific Ocean during mid to late 2002, increasing to near-moderate strength by January 2003. Normally, only the strongest El Nino patterns produce a widespread, well-defined effect on California’s weather. Weaker El Nino’s usually have less correlation and/or effect on the weather patterns in California.

Current Weather Conditions – Northern California

The bulk of northern California has not been affected by drought over the past two years. A notable exception has been the extreme east and northeast sections, which are adjacent to the Great Basin, where extensive moderate to extreme drought exists. For the current cool season, precipitation has ranged from 95-125% of normal west of about Alturas-Williams-Stockton, and from 65-85% to the east of that line (see Fig. 1). In general, November and February had below normal precipitation totals around the north state. December was quite wet over much of the Geographic area, while January ranged from above normal in the north to below normal in the south. The snowpack from the Cascade/Sierras westward began to accumulate nicely in December 2002, but warmer storms in January 2003, along with a few sunny interludes, altered this pattern. This has left end-of February snow coverage below normal for the 4000-6000’ elevation range. On the drier eastside, the snow pack is only at 45-70% of normal.

Figure 1

Mean temperatures thus far this winter have varied from near-normal in northwest California, to 2-4° above normal in counties bordering Nevada (see Figure 2). For the most part, even modified arctic air masses have not even approached the north state. Humidity readings were generally high in December and January, but averaged below normal in November and February. There were two strong windstorms in northern California during December 2002, both occurred by mid-month. Southerly wind gusts reached 65-75 mph in the Sacramento Valley, and to 75-90 mph along the coast and over higher inland terrain. These storms produced areas of blow-down and other wind damage over a large range of elevations.

Figure 2

Current Weather Conditions – Southern California

Precipitation for various time periods, ranging from six months back to four years, range from around 70-90% of normal over the northern areas to as little as 30-50% southern areas. Drought conditions have been most severe over the far southern areas, with the situation being much less severe as we move further north.

The winter season so far has exhibited three distinct circulation patterns. The winter started out with a moist, onshore flow bringing significant precipitation to the area from November into early December. The weather pattern changed to a dominant high- pressure ridge pattern for much of December through January, which resulted in dry weather along with very warm temperatures, especially in the southern areas. In fact over some of the far southern areas, January of 2003 was the warmest January on record, with numerous daily high maximum temperature records broken. As an example, the last day of January, Riverside reported the highest temperature in the U.S., with 97°. Except for January, the winter period had temperatures that were generally near normal. The moist, onshore flow pattern returned in February. This brought a return of significant precipitation for much of the area, as well as, an increase in snowfall to the far southern forests. Overall, winter precipitation was similar to last year over the northern areas and showed significant improvement over the southern areas.

For the winter season, snowfall throughout the forests ranged from near normal far northern forests to well below normal southern forests, with some minor improvement in snowfall southern areas at the time this report was written.

Current Fuel Conditions - Northern California

Currently dead fuel moistures are high and fuels unavailable for consumption due to winter precipitation ranging from 65-125% of normal. 1000-hour fuel moistures currently range from 19 to 35% and average 24% at the 11 USFS severity stations (Figure 3). They are similar to last year’s values for the same time, which is about 5% below average. One of the highest areas of concern is in NE California east of the Sierra Cascade crest. The cumulative effect of 2-3 years of below normal precipitation has affected fuel moisture recovery. Two significant wind events in December left scattered timber blow down across Northern California. These storms produced areas of blow-down over a large range of elevations increasing fuel loading. Tree mortality from insects and disease has also affected numerous areas. The majority of live fuels (brush, chaparral) are dormant and have corresponding low live fuel moistures. The exception is at elevations below 1000’ where some of the live fuels have started to break dormancy.

Figure 3

Current Fuel Conditions - Southern California

Currently, 1000-hour fuel moistures at severity weather stations through most of the Geographic Area are around record low levels. Recent precipitation has moderated these conditions. The only stations showing near average levels for this time of year are on the three southernmost Forests.

These levels are indicative of the long-term drought throughout the area. The 48-month Percent of Average Precipitation chart through the end of January 2003 (Figure 4) shows the southern and eastern portions of the Geographic Area at 50-70% of average precipitation over the last four-year period, and the area around the Sierra Mountains at 70-90% of average precipitation. This drought has resulted in widespread timber and brush mortality throughout the southern portion of the area. There are significant large patches of heavy brush die-back on all of the five southern Forests, and many of these areas have not burned in over 100 years. The southernmost area of the Sierra Mountains has widespread areas of freshly killed standing red-needled pine totaling over 90,000 acres. The combination of drought and resulting heavy fuel loads have contributed significantly to large fire occurrence in the past three years. Figure 4

Areas of the other four southern Forests are experiencing varying levels of brush and timber kill caused by a combination of drought, overstocking, bug-kill, Sudden Oak Death Syndrome, and frost kill several years ago. Timber mortality has increased quickly and continues to spread exponentially, especially in high-density urban interface areas. The Los Padres, Angeles, and Cleveland National Forests have low to moderate levels while the San Bernardino NF has moderate to high levels of brush and timber mortality. The San Bernardino NF appears to be in the most severe fuel situation, with heavy tree mortality and brush die-back. Current timber estimates include 151,000 acres with some significant degree of mortality. In the worst area, timber mortality around the community of Lake Arrowhead ranges from 15-35% on north aspects to 80% on south aspects, with heavy brush kill throughout the area. Areas on the Angeles and Cleveland National Forests have similar tree and brush mortality ranges from 15-70%.

Climate and Weather Outlook through August 2003

The El Nino appears to have begun to wind down, and it is not expected to be a significant factor by early fire season 2003. Drought conditions in southern California are expected to ease somewhat during the spring months. Consensus forecasts for temperatures and precipitation were developed for both March-April-May and June-July-August. These were produced by a group of climatological experts, mainly from the federal government. These California climate and weather Outlooks do not significantly deviate from the consensus of the climate forecasters, as their forecast is considered the best available guidance.

Figure 5

Northern California - Spring (March through May)

For March 2003, northern California is expected to see temperatures averaging near to just below normal. Several Pacific frontal systems are expected to come through during the month. These will be characterized by light to moderate precipitation, cool temperatures, and lower-than-normal snow levels. Total March precipitation is expected to vary from 65-100% of normal around northern California. April is forecast to have temperatures ranging from 1-3° above normal, with precipitation totaling 60-90% of normal. May should average 1-4° warmer-than-normal, with expected precipitation 50-80% of normal. This combination over the spring months will likely keep the snowpack below normal for elevations below 5500’ or 6000’. Drying North to NE winds typically increase in frequency during late April and May, a trend that is expected for this year too. These winds often bring accelerated drying in the Sacramento Valley during May, compared to what you would expect considering only precipitation and temperature effects.

Northern California - Summer (June through August)

The June-August forecast covers at least the first half of the expected fire season. Following with the climate experts’ consensus forecast, this period is forecast to have temperatures within 2° of normal. Precipitation has a slightly greater chance of being below normal than above. Normally this 3-month period is hot and dry in California’s Mediterranean climate, so even if conditions turn out a little cooler and/or wetter than normal, it will still be rather hot and dry overall. Lightning occurrence in 2003 has a very good chance of exceeding that in 2002, as last year was well below the 10-year average amount. Several 1-4 day episodes of gusty north winds can be expected during June, but July and August will have mainly local wind patterns predominating.

Southern California - Spring (March through May)

The expectations are that we will see additional moist, Pacific storms moving through the area during March and April. Most of these weather systems will be relatively cold bringing some increase to the snowpack in the forests, especially in the southern forests. Precipitation for March and April are expected to range from near normal northern areas to somewhat above normal southern areas. Temperatures for March and Aril are expected to average near normal, with alternating cool and warm periods with an absence of extreme temperatures. As we move into May, the large-scale circulation should transition toward a more summer-like weather pattern. Precipitation potential will be decreasing in May. Precipitation is expected to be near normal over much of the area. It should be noted that normal precipitation in May decreases considerably, and is essentially insignificant over much of the area (especially southern areas). Temperatures in May are expected to move up to somewhat above normal.

Southern California - Summer (June through August)

No significant precipitation is expected over the area, with the normal few periods of July and August thunderstorms over the mountains and deserts. Temperatures should average near to a little above normal over the entire area. There could be a slight increase in lightning activity over that experienced during the 2002 fire season. For the Southern California GACC area, above or below normal temperatures or above or below normal precipitation is not a critical factor for our fire activity levels. This area is normally hot or very hot, and either dry or very dry during this three month summer period. The message here is, above or below normal temperatures, as well as above or below normal precipitation, is not a significant factor with respect to predicting a fire season activity level (number or fires, number of large fires, severity of fire season). For our area, the important factor will be ignition sources.

Northern California - Fuels Outlook

Fuels availability for consumption is greatly dependent upon spring temperatures and precipitation patterns. March, April, and May will be the most important months to monitor for green-up of live fuels and drying of dead fuels. Below normal snow coverage in the 4000-6000’ elevation range has the potential to lead to earlier drying of dead fuels, earlier green up and curing of both herbaceous and woody fuels.

One of the highest areas of concern is in NE California east of the Sierra Cascade where the cumulative effect of 2-3 years of below normal precipitation has affected fuel moisture recovery. Both fine and large dead fuels will become available earlier in the season and can be expected to reach critical levels earlier than west of the Sierra/Cascade crest. Indications from the current climate and weather outlook is that fire season will start earlier in this area and be of longer duration.

Special fuel considerations include areas of blow down and tree mortality. Two significant wind events in December left scattered timber blow down over a large range of elevations. Many areas have not been adequately assessed to determine the distribution and increase in fuel loading. There has been increased tree mortality from disease and bark beetle activity the past two years. This trend is forecasted to continue especially in areas that receive 80% or less of normal precipitation. Areas with blow down and/or mortality will see increased potential for higher intensity fires, torching, crowning, and spotting.

Southern California - Fuels Outlook

For the spring, the majority of fire potential lies in the areas with high levels of bug-killed trees and brush die-back including and south of the Sequoia NF. Herbaceous fuels should remain green through early May and during this period fire potential will remain low. Fire ignitions from any source into dead brush or timber could become well established.

Fire potential will increase northward as warming and drying occurs. Even if current drought conditions are mitigated through additional spring precipitation, the effects of the long-term drought on forest fuels in most portions of the area will not be mitigated. As a result, the current expectation for the summer is for above normal fire potential. Large acreage amounts and high fire growth days in 2002 are indicative of the potential that remains in 2003 due to drought and widespread dead fuels.

The most critical areas are expected to be in those portions with heavy tree mortality and brush die-back. The most critical areas will continue to be the urban interface areas in and around the four southern Forests. San Bernardino, Riverside, and San Diego Counties have requested assistance from the state of California for disaster mitigation related to the fire threat in urban interface communities. These mountain and foothill communities have significant populations and limited means of egress. The significant concentrations of standing dead trees and brush die-back in the area increase the potential for fire to spread rapidly through continuous fuels and contributes to the resistance to control. Evacuation and firefighting efforts in these communities would be difficult and dangerous. The population of Lake Arrowhead on the San Bernardino NF alone has 35,000 structures with an estimated population of 100,000. Total commercial and residential values in the Lake Arrowhead area alone are estimated at $7.4 billion. Other communities on the Forest have similar potential problems and losses.

Fire Occurrence and Resource Outlooks

Given the current conditions and predicted fire weather in NOPS, fire occurrence will most likely be above the 2002 fire season as it was statistically below 10-year average. Initial attack response will be covered by drawn down levels consistent with fire weather and fire danger within predictive service areas. Historically, occasional incident management team (IMT) deployment can start as early as April. Multiple IMT deployment normally starts in July. August historically results in three or more incident management teams at the same time. This is also true for SOPS during August, creating competition for resources. The average team deployment for NOPS decreases in the month of September, and lessens the competition for resources between NOPS and SOPS (based on ten year average).

Given the current fuel conditions and predicted fire weather in the Southern California Geographic Area, initial attack response should be covered by draw down levels that are consistent with fire danger and fire activity. Historically, Incident Management Team deployments have occurred throughout the year, although they are most likely between April and November. The months of July through September typically result in two or more IMT deployments in the area at the same time. Although large fire activity typically decreases in late fall, the potential for Santa Ana winds remains through the fall and winter months and can result in significant, complex events with large resource demands.

Federal Suppression Resources

In general, numbers of fire suppression resources (engines, crews, and helicopters) in California for the 2003 fire season will be equivalent to 2002 or slightly greater. Any increase in resource numbers will be due to the National Fire Plan. Federal resources will be at full strength by approximately the first of June. There are five Type 1 and five Type 2 Incident Management Teams available from California.

There will be a decrease of federal heavy air tankers of which three were based in California. The distribution of federal air tankers will be the responsibility of the National Interagency Coordination Center (NICC) based on predictive services.

There will be a reduction of lead planes available in the national system. Allocation of these resources is yet to be determined. Alternative platforms for this mission are being explored.

State Suppression Resources

In general, numbers of fire suppression resources (engines, crews, helicopters, and air tankers) for California Department of Forestry (CDF) will be at base level funding. There are ten CDF Incident Management Teams available from California.

The availability of the California National Guard helicopters will be questionable this fire season due to military commitment.

Future Scenarios and Probabilities

The consensus of this team was that creating multiple future scenarios and probabilities was premature for California. The effect of weather during March and April on fuels is essential to extrapolate future scenarios of fire danger beyond the expectation of near normal. There was a general weather projection developed for spring and summer with a confidence level of 60-70%. Specific areas of concern are the severe bug kill areas in Southern California and the continued drought conditions of Eastern Modoc plateau and east side of northern California.

Management Implications and Concerns

• Management of drawn down levels to compensate for plausible lack of air tanker support for initial attack and large fire support.

• Helicopters from the California National Guard and private industry may not be as readily available in support of large fires due to military support.

• Current commitment of overhead and incident management teams to multiple high priority all-risk incidents, during fire season will create competition for available resources in support of large fire support.

• Fatigue for some of the resources deployed early in the all risk situations will need to be monitored.

Team Members

John Snook - Fire Weather Meteorologist, Redding Interagency Fire Weather Center

Ron Hamilton - Fire Weather Meteorologist, Riverside Interagency Fire Weather Center

Mike Lococo - Intelligence Officer, USFS, Northern California Geographic Area Coordination Center

Vanessa Burnett - Intelligence Officer, USFS, Southern California Geographic Area Coordination Center

Susie Stingley-Russell - NZ Deputy Coordinator, USFS, Northern California Geographic Area Coordination Center

Larry Hood - Fire Fuels Specialist, USFS, Lassen National Forest

Beth Little, Regional RAWS Coordinator, USFS