Today, in the second part of this week's look at the challenges of the Columbia, we'll talk about the upriver leg of the river from Astoria to Portland. A look at the unique issues river pilots face on ships transiting to and from ports like Longview, Kalama, Vancouver and Portland.

Why the Columbia River is so challenging

I talk about this topic from time to time on the show, because there are so many facets to it. Today we’ll take a look at the challenges the river poses for arriving ships, from the unusual underwater geology offshore, to the daunting currents along the winding river corridor. It’s a matter for experienced marine pilots who make critical navigational decisions on the fly every day.

What we know about the Carnival Panorama cruise ship's return to Astoria.