Trevor Anderson

Split sidebars and widget areas into responsive columns.
Two simple widgets are provided, “Layout: New Column” and “Layout: New Column on New Row”.
Simply place these in your widget area where you’d like to create a new column (split) or new row of columns.
Gutter size and responsive collapse options are available in the Customizer -> Widget Columns panel.

Tuxedo Responsive Widget Columns

Just tested this plugin, and it works exactly as I hoped for. I can now have complex layouts in any widget areas. 
Of course it's best used for horizontal widget areas like footers, etc...



Works perfectly!

Split sidebars and widget areas into responsive columns.

Automattic

WooThemes

Matt Cohen

With WooSidebars, it’s possible to change the widgets that display in a sidebar (widgetized area) according to a context (for example, a specific page, a specific blog post, certain categories or the search results screen). Setting up a custom widget area to display across multiple conditions is as easy as a few clicks.
Looking for a helping hand? <a href="https://woocommerce.com/documentation/plugins/woosidebars/" rel="nofollow ugc">View plugin documentation</a>.
Looking to contribute code to this plugin? <a href="https://github.com/woocommerce/woosidebars/" rel="nofollow ugc">Fork the repository over at GitHub</a>. Please also read the CONTRIBUTING.md file, bundled within this plugin.

WooSidebars

WooSidebars adds functionality to display different widgets in a sidebar, according to a context (for example, a specific page or a category).

Tuxedo Responsive Widget Columns vs WooSidebars