hi kb8wfh, sorry to hear about the thunderstorms,
this looks like reboot loop, and may be due to 1 or more drives encountering errors during the boot up sequence, (or possibly still something to do with power).
am not sure if you are still within support, though if you are it will probably be best to raise a ticket with the support team (which i believe can also be raised as a pay-per-incident in case out of support, if you would wish)
can i check if you happened to already have had a running computer with dashboard, when you were powering it up, and if so, if it happened to show or recognise anything in dashboard during this booting up and rebooting sequence?
if the 3rd drive was showing a solid yellow light, before the outage, i think that may just be coincidence, and that the drobo was probably indicating a yellow light there if that drive happened to be one of the smaller-sized drives inside it?
while the safest thing would probably be to have the drives fully block cloned, there are some relatively straightforward steps you could try if comefortable for example these:
(important: you may already be aware, though just to mention that a set of diskpack drives should only be removed or inserted in their entirety, and only when power is all Off and cables unplugged)
with this in mind, one of the things you could try, could be to try putting your drobo into a read-only mode, for example as mentioned here: http://www.drobospace.com/forums/showthread.php?tid=143618
(and it might help to stabalise the drobo, at least to still be able to access and copy data to somewhere else for the time being - it has helped several users with a mixture of issues before, and is probably worth giving it a go)
though it is probably worth having a look here first as well:
& related link here: https://myproducts.drobo.com/article/AA-01615
just to become more familiar with the steps, but also because it mentions some additional checks you could try in case the issue is with power (or with a UPS or surge protector, that may possibly have been damaged and is partly working, but which your drobo is still connected to?)
you may also need to remove the drives as mentioned in https://myproducts.drobo.com/article/AA-01649 in order to be able to get into dashboard to enable readonly mode (and after the drobo is in readonly mode, you should only put your diskpack drives back into where they were before, but only when power is all Off again and cables unplugged - this should hopefully then see your repopulated drobo boot back up into read only mode.
if there are still problems though (especially if an empty drobo is not booting up as expected, as mentioned in https://myproducts.drobo.com/article/AA-01649 then there may be an issue with the main drobo hardware - though i think in most cases if the diskpack drives themselves are ok, and if the main hardware/chassis has a problem, is will be better… for example, when my drobo-s-gen2 chassis had an issue with the power toggle switch, i was able use a migration process to migrate my diskpack to another compatible replacement model of the same, and access all my data again)