Tule Fog Driving Season

[Max Rockatansky]

The Fresno Area had it's first bout of Tule Fog yesterday after the first round of winter storms rolled through.  Granted I know it hasn't been quite to the levels of 2016 and over previous winters with heavy amounts of moisture.  Took this photo yesterday in about 500 foot visibility heading southbound on Clovis Avenue approaching CA 99:

99CA1 by Max Rockatansky, on Flickr

This morning my area was down to under 200 foot visibility by 7 AM.  Supposedly the next three days will have heavy rain followed by a drop in temperature.  It will be interesting to see how much fog there is by early next week.

[sparker]

Used to hate/fear that shit when taking L.A. - Sacramento trips as a kid.  But the worst tule fog I experienced came later during college, when heading toward a Bear Valley ski trip up 99 circa 1969 or so -- could barely see 5 feet in front of the windshield.  I do remember that the fog broke once I was on CA 59 between Merced and Snelling, with "clear sailing" all the way from there.  Nevertheless, not an experience I care to repeat!

[mgk920]

This is the periodic fog that has the CHP running their cruisers as 'pace cars' to lead traffic on nearby I-5, too, correct?

Mike

[Max Rockatansky]

This is the periodic fog that has the CHP running their cruisers as 'pace cars' to lead traffic on nearby I-5, too, correct?

Mike

The same, two years ago I was driving a bunch of back roads to avoid those pace cars.  I figufedthe best way to defend myself was to avoid everyone else on CA 41 and CA 198.  198 had a 50 Car pileup in the fog back in 2016. 

[Max Rockatansky]

Used to hate/fear that shit when taking L.A. - Sacramento trips as a kid.  But the worst tule fog I experienced came later during college, when heading toward a Bear Valley ski trip up 99 circa 1969 or so -- could barely see 5 feet in front of the windshield.  I do remember that the fog broke once I was on CA 59 between Merced and Snelling, with "clear sailing" all the way from there.  Nevertheless, not an experience I care to repeat!

It was down to about 50 feet a couple times last year south of Fresno.  I found that pulling up the GPS was a handy way of knowing where cross streets were located.  Drives that normally take me 30 minutes we're becoming hour plus long ordeals.  I've heard similar stories to yours about the 1960s fog being especially thick.  Probably played a large part in why I-5 skirts the floothills of the Coast Ranfes since it's usually over the fog line. 

[sparker]

Used to hate/fear that shit when taking L.A. - Sacramento trips as a kid.  But the worst tule fog I experienced came later during college, when heading toward a Bear Valley ski trip up 99 circa 1969 or so -- could barely see 5 feet in front of the windshield.  I do remember that the fog broke once I was on CA 59 between Merced and Snelling, with "clear sailing" all the way from there.  Nevertheless, not an experience I care to repeat!

It was down to about 50 feet a couple times last year south of Fresno.  I found that pulling up the GPS was a handy way of knowing where cross streets were located.  Drives that normally take me 30 minutes we're becoming hour plus long ordeals.  I've heard similar stories to yours about the 1960s fog being especially thick.  Probably played a large part in why I-5 skirts the floothills of the Coast Ranfes since it's usually over the fog line. 

Kinda makes one wish that the CA 65 corridor, uphill a bit as it would have been (at least north of CA 180), wouldn't have been relegated to the rear of state/regional planning efforts.  Guess even avoiding tule fog has its fiscal limits!

[Max Rockatansky]

Used to hate/fear that shit when taking L.A. - Sacramento trips as a kid.  But the worst tule fog I experienced came later during college, when heading toward a Bear Valley ski trip up 99 circa 1969 or so -- could barely see 5 feet in front of the windshield.  I do remember that the fog broke once I was on CA 59 between Merced and Snelling, with "clear sailing" all the way from there.  Nevertheless, not an experience I care to repeat!

It was down to about 50 feet a couple times last year south of Fresno.  I found that pulling up the GPS was a handy way of knowing where cross streets were located.  Drives that normally take me 30 minutes we're becoming hour plus long ordeals.  I've heard similar stories to yours about the 1960s fog being especially thick.  Probably played a large part in why I-5 skirts the floothills of the Coast Ranfes since it's usually over the fog line. 

Kinda makes one wish that the CA 65 corridor, uphill a bit as it would have been (at least north of CA 180), wouldn't have been relegated to the rear of state/regional planning efforts.  Guess even avoiding tule fog has its fiscal limits!

Turns out whoever plotted out the El Camino Viejo and Stockton-Los Angeles Road really knew what they were doing in retrospect. 

[J N Winkler]

For a Sacramento-Los Angeles trip during tule fog season, is it typically worth a 160-mile detour (SR 14/US 395/US 50 rather than I-5 or SR 99) to avoid fog?

[Max Rockatansky]

For a Sacramento-Los Angeles trip during tule fog season, is it typically worth a 160-mile detour (SR 14/US 395/US 50 rather than I-5 or SR 99) to avoid fog?

Hell I'd take US 395 and US 50 any day of the week just for the eastern Sierras in addition to Tahoe.  That said the Tule Fog is rarely bad enough to stop travel for very long whereas chain control zones on US 395 and US 50 are just as common in the winter. 

[sparker]

For a Sacramento-Los Angeles trip during tule fog season, is it typically worth a 160-mile detour (SR 14/US 395/US 50 rather than I-5 or SR 99) to avoid fog?

Hell I'd take US 395 and US 50 any day of the week just for the eastern Sierras in addition to Tahoe.  That said the Tule Fog is rarely bad enough to stop travel for very long whereas chain control zones on US 395 and US 50 are just as common in the winter. 

If you're going to try to avoid the Valley in general -- and you don't want to deal with winter snow conditions, just use US 101 up to San Jose and then I-680 and I-80 the rest of the way.  Of course, you'll need to leave either very early or very late to avoid I-680 during commute times.  Alternately -- I've found that I-5 north of CA 152 sits elevated enough from the valley floor that only the very worst tule fog affects it; taking EB 156 to EB 152 to NB 33 to NB I-5 might be a viable option.  The worst tule fog seems to occur east of the San Joaquin River and the Fresno Slough; so a Tracy-Sacramento jaunt shouldn't be that troublesome (nevertheless, I'd check to see if I-5 or CA 99 offered the lesser fog problems through that area). 

[gonealookin]

For a Sacramento-Los Angeles trip during tule fog season, is it typically worth a 160-mile detour (SR 14/US 395/US 50 rather than I-5 or SR 99) to avoid fog?

Hell I'd take US 395 and US 50 any day of the week just for the eastern Sierras in addition to Tahoe.  That said the Tule Fog is rarely bad enough to stop travel for very long whereas chain control zones on US 395 and US 50 are just as common in the winter. 

Isn't that fog usually worst in the morning?  It seems like every time I read about one of those huge pileups it happened between maybe sunrise and 9 a.m.

When a winter storm is moving through there generally wouldn't be any fog as there's enough atmospheric circulation to keep it from forming.  It's those periods between storms when the ground in the valley is wet and radiational cooling under the clear sky allows the temperature to drop to the dewpoint that fog forms.  There are days when coastal locations such as Santa Cruz are sunny and in the balmy 70s while valley locations, even in parts of the Bay Area, remain in the clammy 40s.  As far as going up the eastern Sierras and over the mountains, because the fog forms in otherwise clear weather, valley fog issues and mountain chain controls are pretty much mutually exclusive.

[theroadwayone]

They mentioned it in the "Dangerous Roads" episode of Modern Marvels on the History Channel way back when.

[Max Rockatansky]

For a Sacramento-Los Angeles trip during tule fog season, is it typically worth a 160-mile detour (SR 14/US 395/US 50 rather than I-5 or SR 99) to avoid fog?

Hell I'd take US 395 and US 50 any day of the week just for the eastern Sierras in addition to Tahoe.  That said the Tule Fog is rarely bad enough to stop travel for very long whereas chain control zones on US 395 and US 50 are just as common in the winter. 

Isn't that fog usually worst in the morning?  It seems like every time I read about one of those huge pileups it happened between maybe sunrise and 9 a.m.

When a winter storm is moving through there generally wouldn't be any fog as there's enough atmospheric circulation to keep it from forming.  It's those periods between storms when the ground in the valley is wet and radiational cooling under the clear sky allows the temperature to drop to the dewpoint that fog forms.  There are days when coastal locations such as Santa Cruz are sunny and in the balmy 70s while valley locations, even in parts of the Bay Area, remain in the clammy 40s.  As far as going up the eastern Sierras and over the mountains, because the fog forms in otherwise clear weather, valley fog issues and mountain chain controls are pretty much mutually exclusive.

Yes, the fog rarely ever lasts past 9 AM.  It can last all day but I can count the instances (since I've lived here) where that has happened on one hand.  Calm weather in the Central Valley generally means some sort of fog in the winter but tame driving conditions in the Sierras in general.  The second we get a hint of a storm here in the Central Valley the air swirls up too much for fog but you can almost certainly count on some form of chain control above 5,000 feet in the winter months.

[Max Rockatansky]

First big fog of the season hit today with a lot areas around Fresno reporting under a quarter mile visibility.  Really after all the rain here and snow in the Sierras last week it's not really a shock that the fog came out so fast when the air stabilized.