Are there some quantum factors involved here?

No, just electromagnetism.   If a charge is moved, the strength and direction of the electric and magnetic fields in the surrounding space change as well, and the perturbation travels outward at the speed of light. So in Veritasium's circuit, the charges near the light bulb on the far end of the wire, just 1 meter away, feel a force due to the movement of the charges across the closed switch, and they feel that force just 1 meter divided by the speed of light (about 3.3 nanoseconds) later. 

This initial movement of charge does not represent the full current (whatever the battery voltage is divided by the total resistance of the circuit), which takes longer to build up, since the electrons all throughout the circuit take some time to start moving and reach a steady flow.

Perhaps we can use this image to visualise: Think of the switch shouting to the electrons to begin moving, but the command travels at the speed of light rather than at the speed of sound.  The electrons start to move as soon as they hear the command, but it will take time to get a steady flow because all the electrons need to hear the command before they all can move in unison.

The way I pictured it in my mind is the way an electric heater works (I have space heaters).  So as soon as I turn it on I can tell it's on (it hums) but it takes a little bit of time for it to fully "turn on" because that doesn't happen until all the coils have the current flowing through them.  That must be analogous to all the electrons hearing the command and moving in unison.  It definitely seems to take a bit of time for the full current to build up.

A little inspired by the video I tried to photograph some snowflakes today.  I don't have any macro lenses, so my best option was my mobile phone, which has its limitations.  Anyway, there's some very light snow today, no wind and -8C, so this should mean idea conditions for some good snow crystals (around -15C at the cloud base seems reasonable).

We had similar conditions here the other night, and when I went out I noticed the older powdery snow was covered with a fresh layer of large dendritic flakes, sparkling like jewels. I don't have a macro lens either, but tried a few shots with my cell phone and 10x jeweler's loupe.



A different snowflake several meters away, but almost exactly the same shape. It must have gone through very similar conditions.


This one has a few more branches starting.


The most amazing thing to me is not even how they get their shapes (which the video demonstrated so well how that happens), but that such thin structures can survive an impact on a surface which is, on their scale, incredibly rough and spiky. You'd think they would all be ripped apart or shattered. Many are, of course, but it was not difficult at all to find a lot of intact ones. That the intact ones reflect the light like little mirrors helps.

Maybe their structure is so strong and stable that's why it survives impact, Wats?  Nature seems to select for such structures.  If I want to do this with a regular camera would my collection of close up filters help?  I have them in 58mm and 67mm thread size from Tiffen.  They have a very shallow DOF.

The most amazing thing to me is not even how they get their shapes (which the video demonstrated so well how that happens), but that such thin structures can survive an impact on a surface which is, on their scale, incredibly rough and spiky.

I think the simple answer to that is the quadratic nature of size versus the cubic nature of mass.  Snowflakes are extremely light compared to their size if we apply our everyday scale, and the air remains thick and at the snowflake scale the air becomes more like a fluid, again if we apply our everyday scale.

The most amazing thing to me is not even how they get their shapes (which the video demonstrated so well how that happens), but that such thin structures can survive an impact on a surface which is, on their scale, incredibly rough and spiky.

I think the simple answer to that is the quadratic nature of size versus the cubic nature of mass.  Snowflakes are extremely light compared to their size if we apply our everyday scale, and the air remains thick and at the snowflake scale the air becomes more like a fluid, again if we apply our everyday scale.

So the snowflakes that have the highest liquid equivalency ratio would be the most durable?  We normally have 10:1 to 12:1 snow here but when it's very cold we've had 40:1 to even 80:1 snow.  Wet snow is more like 5:1 to 8:1 and sleet is 2:1

So the snowflakes that have the highest liquid equivalency ratio would be the most durable? 

I don't think liquid equivalency makes sense for individual snowflakes.  Snowflakes quickly transform and pack denser together, which is what increases the liquid equivalency.

So the snowflakes that have the highest liquid equivalency ratio would be the most durable? 

I don't think liquid equivalency makes sense for individual snowflakes.  Snowflakes quickly transform and pack denser together, which is what increases the liquid equivalency.

For whatever reason it seems like drier snow melts more quickly, the wetter the snow the longer it lasts, all else being equal (including temperature.)

For whatever reason it seems like drier snow melts more quickly, the wetter the snow the longer it lasts, all else being equal (including temperature.)

"Wetter" or high liquid equivalent snow lasts longer because its density is higher. That is, there is more to melt in a given volume. Solid ice will melt even more slowly.  On the other hand, wet snow often means melting snow, while dry powdery snow often means colder conditions.

I agree with midtskogen that liquid equivalency makes little sense for individual snowflakes -- it's more of a bulk property of snow involving how much it is compacted. Individual snowflakes are basically solid but thin plates or needles of ice, though may have small bubbles and defects.

For whatever reason it seems like drier snow melts more quickly, the wetter the snow the longer it lasts, all else being equal (including temperature.)

"Wetter" or high liquid equivalent snow lasts longer because its density is higher. That is, there is more to melt in a given volume. Solid ice will melt even more slowly.  On the other hand, wet snow often means melting snow, while dry powdery snow often means colder conditions.

I agree with midtskogen that liquid equivalency makes little sense for individual snowflakes -- it's more of a bulk property of snow involving how much it is compacted. Individual snowflakes are basically solid but thin plates or needles of ice, though may have small bubbles and defects.

Wats is that why sleet or glaze on top of a snowpack makes it last longer?  It increases the density of the pack, which causes a much slower melt rate?  It also takes away from the albedo of the snow though, which makes it look duller.

I think he explained it well: density.  Solid ice has maximum density and melts the slower.  The more ice in the snow, the more there is to melt.  I don't think the albedo of the snow has much to say, but in spring slopes facing the sun or windswept slopes get free of snow first, and the snow free areas tend to expand from that.  So the snow depth in spring usually shrinks slowly. Snow covered patches rather shrink in area until it quickly disappears, being "eaten" by the low albedo of the surrounding snow free ground.  At very high latitudes or altitudes where the air temperature often stays below freezing in summer, the snow still melts (or sublimates) due to the growing low albedo patches of snow free ground.

Another factor for snow melt is that snow is good at radiating heat at night time if the sky is clear.  The air temperature can be well above freezing, but with no clouds to cover the "cold" sky, the snow looses heat and stay frozen.  So even though the snow gets wet during the day, it refreezes during night.

Thats a good point and something else that also may contribute is that long lasting snowpack has a higher density so the fact that it has lasted for weeks may also keep it lasting longer than newly fallen snow of a similar thickness.  I only noted the albedo because ice seems to make the snow lose its clean white color but even so it still seems to last longer because of its higher density.

A good collection of satellite images of the Tonga eruption:

https://www.youtube.com/watch?v=zoMRwyNhqJ4

The shock wave travelled around the world, and it can easily be picked up by any weather station around the world.  Here's a plot of the atmospheric pressure logged by my weather station, where the shock wave can be seen around 18:30 UTC:

How does this compare to eruptions like Pinatubo and Krakatoa?