1 FALL & WINTER CLIMO AND HAZARDS BRIEFING! Sacramento, CA DET 32 OSA FY08

2 November Climatology (Monthly Averages) l Temp:53F l High Temp:64F l Low Temp:43 l Precipitation:2.2 inches l Clear days:10 l Cloudy days:13 l Partly Cloudy days:7 l Rainy days:7

3 December Climatology (Monthly Averages) l Temp:46F l High Temp:53F l Low Temp:38F l Precipitation:2.8 inches l Clear days:8 l Cloudy days:17 l Partly Cloudy days:6 l Rainy days:9

4 January Climatology (Monthly Averages) l Temp:46F l High Temp:53F l Low Temp:38F l Precipitation:3.7 inches l Clear days:7 l Cloudy days:18 l Partly Cloudy days:6 l Rainy days:10

5 February Climatology (Monthly Averages) l Temp:51F l High Temp:60F l Low Temp:41F l Precipitation:2.8 inches l Clear days:8 l Cloudy days:13 l Partly Cloudy days:6 l Rainy days:9

6 March Climatology (Monthly Averages) l Temp:54F l High Temp:64F l Low Temp:43F l Precipitation:2.6 inches l Clear days:10 l Cloudy days:13 l Partly Cloudy days:8 l Rainy days:9

7 April Climatology (Monthly Averages) l Temp:59F l High Temp:71F l Low Temp:46F l Precipitation:1.2 inches l Clear days:12 l Cloudy days:8 l Partly Cloudy days:10 l Rainy days:5

8 General Winter Hazards l Icing l Turbulence l White Out Conditions l Personnel Activities

9 ICING HAZARDS

10 ICING HAZARDS l Mostly occurs in cloud, but can occur below if.... l 1) Precip is liquid and aircraft skin is below freezing. l 2) Precip is falling from warmer layer on to an aircraft that is in a colder layer below. l Types of Icing l 1) Frost l 2) Rime l 3) Clear l 4) Mixed (This is not a type by itself. It is actually a mixture of Rime and Clear ice.)

11 ICING HAZARDS CONT. l Can Seriously degrade aircraft performance by... l 1) Increasing aircraft weight. l 2) Increasing the drag of the aircraft. l 3) Decreasing lift. l 4) and, Freezing up the aircraft control surfaces. BEWARE. ICING CAN KILL!!

12 WAYS TO MINIMIZE ICING l Remove ice and snow from aircraft before takeoff. l Avoid flying in clouds when outside air temperature is 0 c to -20 c. l Use all necessary anti-ice and de-ice equipment. l If icing is encountered, climb or descend to an altitude where the temperature is warmer than 0 c or colder than -20 c.

13 TURBULENCE HAZARDS

14 TYPES OF TURBULENCE l Most common types during winter are... – Mechanical... l Results when obstructions such as buildings, trees, and rough terrain disrupt smooth wind flow. The degree of this turbulence depends on wind speed and roughness of the obstructions (ie. The higher the wind speed and / or the rougher the surface, the greater the turbulence will be. l Mountain Wave... l Are areas of steady updrafts and downdrafts associated with the mountain wave may extend to as far as 300 miles downstream from a mountain range. Moderate to severe turbulence is common with this type of turbulence.

15 TURBULENCE INTENSITIES ( Note: This is only one tool that can be used for Turb.) IntensityVertical Speed Change Light Moderate Severe Extreme 3-5 kts per 1000 ft 6-9 kts per 1000 ft kts per 1000 ft >15kts per 1000 ft

16 MECHANICAL TURBULENCE LOCATIONS l Mechanical Turbulence Locations... l In or near cumulus or cumulonimbus clouds. l Areas with drastic change in topography. l Areas where winds blow over structures or uneven ground. l In valleys or canyons. l In the vicinity of frontal systems.

17 MOUNTAIN WAVE LOCATION AND INDICATORS l Mountain Wave Turbulence Location... l When winds are greater than 25 kts blowing perpendicular across the tops of mountains. l Mountain Wave Indicators l Blowing dust downwind of high terrain. l Fluctuations of the airspeed indicator and the vertical velocity indicator. l If any of the following clouds are present. – Lenticular clouds – Rotor (Roll) clouds – Cap cloud

18 LOW LEVEL WIND SHEAR l LLWS is the primary or probable cause of several aircraft incidents and accidents worldwide. It is most dangerous within 2,000 feet of the ground. l Where to expect Low Level Wind Shear... l At the top of Radiation inversions. l Near frontal boundaries l Where surface winds are at least 30 kts or more. l Near mountains, and along straits and channels.

19 LLWS CONT. l LLWS Indicators – Abnormal power setting and rate of decent required to maintain glidepath. – Fluctuations in indicated air speed and vertical velocity indicators. – Large difference between IAS and ground speed. – Significant difference between approach wind and reported surface winds.

20 WHITE OUT CONDITIONS

21 WHITE OUT CONDITIONS l Occur when landing or hovering near the ground. l Can occur with very little snow on the ground. l Most often occurs with freshly fallen, fine, dry snow flakes. l Can reduce visibility down to 0 feet in seconds.

22 HAZARDS TO PERSONNEL

23 Cold Weather Injuries l Frostbite – Dress warmly in loose layers – Wear gloves and other cold weather gear when outside for long periods of time – Don’t touch metal or snow with bare hands l Hypothermia – Stay dry and warm l Trenchfoot – Wear dry and insulated boots

24 Windchill l Cold Temperatures combined with strong winds can make it feel very cold l Wind Chill Temperatures – Above -20F = Little Danger – From -20F to -70F = Flesh may freeze in 1 min – Below -70F = Flesh may freeze in 30 sec l Low wind chills can be caused by rotor wash and moving vehicles l Protect Yourself!

25 Driving Conditions l Know the Road Conditions l Drive slow and stay in control l Snow and Ice can sneak up on you due to low visibility l Use your brakes wisely l Use your chains to maintain traction

26QUESTIONS?

27 Thank You For Your Attention! If you have any other questions please contact your local weather facility.